resource/cloudflare_ruleset: allow override + rule enabled to be omitted

[jacobbednarz]

Updates the rules.*.action_parameters.0.enabled to be omitted should
the value not be set.

Closes #1273

[jacobbednarz]

@vences do you know of any other of the enabled fields that are in the same scenario here?

[jacobbednarz]

acceptance tests are good

TF_ACC=1 go test $(go list ./...) -v -run "^TestAccCloudflareRuleset_" -count 1 -parallel 1 -timeout 120m -parallel 1
?   	github.com/cloudflare/terraform-provider-cloudflare	[no test files]
=== RUN   TestAccCloudflareRuleset_WAFBasic
=== PAUSE TestAccCloudflareRuleset_WAFBasic
=== RUN   TestAccCloudflareRuleset_WAFManagedRuleset
=== PAUSE TestAccCloudflareRuleset_WAFManagedRuleset
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetOWASP
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetOWASP
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetOWASPBlockXSSWithAnomalyOver60
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetOWASPBlockXSSWithAnomalyOver60
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetOWASPOnlyPL1
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetOWASPOnlyPL1
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetDeployMultiple
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetDeployMultiple
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithSkip
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithSkip
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithTopSkipAndLastSkip
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithTopSkipAndLastSkip
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetWithCategoryBasedOverrides
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetWithCategoryBasedOverrides
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetWithIDBasedOverrides
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetWithIDBasedOverrides
=== RUN   TestAccCloudflareRuleset_MagicTransitUpdateWithHigherPriority
    provider_test.go:142: Skipping acceptance test as 0da42c8d2132a9ddaf714f9e7c920711 is not configured for Magic Transit
--- SKIP: TestAccCloudflareRuleset_MagicTransitUpdateWithHigherPriority (0.00s)
=== RUN   TestAccCloudflareRuleset_WAFManagedRulesetWithPayloadLogging
=== PAUSE TestAccCloudflareRuleset_WAFManagedRulesetWithPayloadLogging
=== RUN   TestAccCloudflareRuleset_RateLimit
=== PAUSE TestAccCloudflareRuleset_RateLimit
=== RUN   TestAccCloudflareRuleset_TransformationRuleURIPath
=== PAUSE TestAccCloudflareRuleset_TransformationRuleURIPath
=== RUN   TestAccCloudflareRuleset_TransformationRuleURIQuery
=== PAUSE TestAccCloudflareRuleset_TransformationRuleURIQuery
=== RUN   TestAccCloudflareRuleset_TransformationRuleURIPathAndQueryCombination
=== PAUSE TestAccCloudflareRuleset_TransformationRuleURIPathAndQueryCombination
=== RUN   TestAccCloudflareRuleset_TransformationRuleHeaders
=== PAUSE TestAccCloudflareRuleset_TransformationRuleHeaders
=== RUN   TestAccCloudflareRuleset_ActionParametersMultipleSkips
=== PAUSE TestAccCloudflareRuleset_ActionParametersMultipleSkips
=== RUN   TestAccCloudflareRuleset_ActionParametersOverridesAction
=== PAUSE TestAccCloudflareRuleset_ActionParametersOverridesAction
=== RUN   TestAccCloudflareRuleset_ActionParametersHTTPDDoSOverride
=== PAUSE TestAccCloudflareRuleset_ActionParametersHTTPDDoSOverride
=== RUN   TestAccCloudflareRuleset_AccountLevelCustomWAFRule
=== PAUSE TestAccCloudflareRuleset_AccountLevelCustomWAFRule
=== CONT  TestAccCloudflareRuleset_WAFBasic
--- PASS: TestAccCloudflareRuleset_WAFBasic (10.65s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetWithPayloadLogging
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetWithPayloadLogging (10.04s)
=== CONT  TestAccCloudflareRuleset_AccountLevelCustomWAFRule
--- PASS: TestAccCloudflareRuleset_AccountLevelCustomWAFRule (11.58s)
=== CONT  TestAccCloudflareRuleset_ActionParametersHTTPDDoSOverride
--- PASS: TestAccCloudflareRuleset_ActionParametersHTTPDDoSOverride (10.16s)
=== CONT  TestAccCloudflareRuleset_ActionParametersOverridesAction
--- PASS: TestAccCloudflareRuleset_ActionParametersOverridesAction (10.64s)
=== CONT  TestAccCloudflareRuleset_ActionParametersMultipleSkips
--- PASS: TestAccCloudflareRuleset_ActionParametersMultipleSkips (11.14s)
=== CONT  TestAccCloudflareRuleset_TransformationRuleHeaders
--- PASS: TestAccCloudflareRuleset_TransformationRuleHeaders (10.76s)
=== CONT  TestAccCloudflareRuleset_TransformationRuleURIPathAndQueryCombination
--- PASS: TestAccCloudflareRuleset_TransformationRuleURIPathAndQueryCombination (10.55s)
=== CONT  TestAccCloudflareRuleset_TransformationRuleURIQuery
--- PASS: TestAccCloudflareRuleset_TransformationRuleURIQuery (11.26s)
=== CONT  TestAccCloudflareRuleset_TransformationRuleURIPath
--- PASS: TestAccCloudflareRuleset_TransformationRuleURIPath (10.26s)
=== CONT  TestAccCloudflareRuleset_RateLimit
--- PASS: TestAccCloudflareRuleset_RateLimit (10.43s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetDeployMultiple
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetDeployMultiple (110.95s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetWithIDBasedOverrides
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetWithIDBasedOverrides (13.50s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetWithCategoryBasedOverrides
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetWithCategoryBasedOverrides (11.74s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithTopSkipAndLastSkip
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithTopSkipAndLastSkip (13.35s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithSkip
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetDeployMultipleWithSkip (11.02s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetOWASPOnlyPL1
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetOWASPOnlyPL1 (10.86s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetOWASP
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetOWASP (11.28s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRuleset
--- PASS: TestAccCloudflareRuleset_WAFManagedRuleset (10.44s)
=== CONT  TestAccCloudflareRuleset_WAFManagedRulesetOWASPBlockXSSWithAnomalyOver60
--- PASS: TestAccCloudflareRuleset_WAFManagedRulesetOWASPBlockXSSWithAnomalyOver60 (10.24s)
PASS
ok  	github.com/cloudflare/terraform-provider-cloudflare/cloudflare	321.462s
?   	github.com/cloudflare/terraform-provider-cloudflare/version	[no test files]