add custom diff for LBListener forward options

[erhancagirici]

Description of your changes

Fixes the update loop for LBListener.

Will fix #1352

I have:

• Read and followed Crossplane's contribution process.
• Run make reviewable to ensure this PR is ready for review.
• Added backport release-x.y labels to auto-backport this PR if necessary.

How has this code been tested

manual

[mergenci]

Thanks @erhancagirici 🙏 LGTM.

[mergenci]

/test-examples="examples/elbv2/v1beta1/lblistener.yaml"

Uptest failure

[mergenci]

I realized that we should merge this PR after we consume upbound/terraform-provider-aws#276, so I dismissed my approval.

[mergenci]

/test-examples="examples/elbv2/v1beta1/lblistener.yaml"

[mergenci]

/test-examples="examples/elbv2/v1beta1/lblistener.yaml"

[erhancagirici]

/test-examples="examples/elbv2/v1beta1/lblistener.yaml"

[mergenci]

To summarize, Uptest failed because of a regression in LBListenerTarget introduced by Terraform provider version bump v5.68.0. The regression caused the resource to enter an update loop:

2024-10-19T22:45:51+03:00	DEBUG	provider-aws	Diff detected	{"uid": "ac9bbe35-e483-4f51-bfea-10fddcc1ddec", "name": "issue-1352-lbtargetgroup", "gvk": "elbv2.aws.upbound.io/v1beta1, Kind=LBTargetGroup", "instanceDiff": "*terraform.InstanceDiff{mu:sync.Mutex{state:0, sema:0x0}, Attributes:map[string]*terraform.ResourceAttrDiff{\"target_health_state.0.unhealthy_draining_interval\":*terraform.ResourceAttrDiff{Old:\"\", New:\"0\", NewComputed:false, NewRemoved:false, NewExtra:interface {}(nil), RequiresNew:false, Sensitive:false, Type:0x0}}, Destroy:false, DestroyDeposed:false, DestroyTainted:false, RawConfig:cty.NilVal, RawState:cty.NilVal, RawPlan:cty.NilVal, Meta:map[string]interface {}(nil)}"}

The update loop was present in the Uptest we ran in the version bump PR, but we overlooked it because we only checked whether LBListener panicked, which it did.

[mergenci]

Thanks for your weekend operation Erhan 🙂 Now LGTM for real.

[erhancagirici]

/test-examples="examples/elbv2/v1beta2/lblistener-forward-single-targetgroup.yaml"

[erhancagirici]

/test-examples="examples/elbv2/v1beta2/lblistener-forward-multiple-targetgroups.yaml"

[erhancagirici]

/test-examples="examples/elbv2/v1beta2/lblistener-forward-single-targetgroup.yaml"

[erhancagirici]

/test-examples="examples/elbv2/v1beta2/lblistener-forward-multiple-targetgroups.yaml"

[erhancagirici]

added new example manifests to cover forward default action through default_action.0.forward (on top of the current example that default_action.0.target_group_arn) and the new tests also pass.

single target group: https://github.com/crossplane-contrib/provider-upjet-aws/actions/runs/11436536351/job/31814191141
multiple target groups: https://github.com/crossplane-contrib/provider-upjet-aws/actions/runs/11436538196/job/31816315624