Add force destroy support for Transfer Server

[teraken0509]

When destroy aws_transfer_server resource with users not managed by terraform, the apply would be failed.

Changes proposed in this pull request:

• Add force_destroy attribute to aws_transfer_server resource

Output from acceptance testing:

$ make testacc TESTARGS='-run=TestAccAWSTransferServer_forcedestroy'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./... -v -parallel 20 -run=TestAccAWSTransferServer_forcedestroy -timeout 120m
?   	github.com/terraform-providers/terraform-provider-aws	[no test files]
=== RUN   TestAccAWSTransferServer_forcedestroy
=== PAUSE TestAccAWSTransferServer_forcedestroy
=== CONT  TestAccAWSTransferServer_forcedestroy
--- PASS: TestAccAWSTransferServer_forcedestroy (33.98s)
PASS
ok  	github.com/terraform-providers/terraform-provider-aws/aws	34.046s
...

[bflad]

Nice work, @kterada0509, especially writing up the covering acceptance test. 🚀

--- PASS: TestAccAWSTransferServer_disappears (3.90s)
--- PASS: TestAccAWSTransferServer_apigateway (7.93s)
--- PASS: TestAccAWSTransferServer_forcedestroy (8.57s)
--- PASS: TestAccAWSTransferServer_basic (11.56s)

[bflad]

This has been released in version 1.54.0 of the AWS provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!