fix: Allow specifying ARN as sns_topic_name if region/account is different for aws_cloudtrail

[acwwat]

Description

This PR is to fix an issue introduced by #41168 where sns_topic_name is always read as the name instead of ARN, even for an SNS topic in another region or account, for the aws_cloudtrail resource.

The documentation is NOT specify that one can specify an SNS topic ARN as sns_topic_name, nor does it specify that the the SNS topic can be in a different region (and presumably different account). I will open an AWS support case separately to seek clarification, but for now we need to fix the regression.

If you think think we should simply roll back the change and fix it again for 6.x for better compatibility, let me know.

Relations

Closes #41262

References

n/a - documentation is wrong anyway...

Output from Acceptance Testing

Note: I am not sure why TestAccCloudTrail_serial/Trail/migrateV0 always fail in my environment.

$ make testacc TESTS="TestAccCloudTrail_serial/Trail/" PKG=cloudtrail
make: Verifying source code with gofmt...
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go1.23.5 test ./internal/service/cloudtrail/... -v -count 1 -parallel 20 -run='TestAccCloudTrail_serial/Trail/'  -timeout 360m -vet=off
2025/02/06 21:50:36 Initializing Terraform AWS Provider...
=== RUN   TestAccCloudTrail_serial
=== PAUSE TestAccCloudTrail_serial
=== CONT  TestAccCloudTrail_serial
=== RUN   TestAccCloudTrail_serial/Trail
=== RUN   TestAccCloudTrail_serial/Trail/enableLogging
=== RUN   TestAccCloudTrail_serial/Trail/snsTopicNameAlternateRegion
=== RUN   TestAccCloudTrail_serial/Trail/tags
=== RUN   TestAccCloudTrail_serial/Trail/eventSelectorDynamoDB
=== RUN   TestAccCloudTrail_serial/Trail/insightSelector
=== RUN   TestAccCloudTrail_serial/Trail/disappears
=== RUN   TestAccCloudTrail_serial/Trail/globalServiceEvents
=== RUN   TestAccCloudTrail_serial/Trail/multiRegion
=== RUN   TestAccCloudTrail_serial/Trail/organization
    trail_test.go:230: this AWS account must be the management account of an AWS Organization
=== RUN   TestAccCloudTrail_serial/Trail/kmsKey
=== RUN   TestAccCloudTrail_serial/Trail/eventSelectorExclude
=== RUN   TestAccCloudTrail_serial/Trail/advancedEventSelector
=== RUN   TestAccCloudTrail_serial/Trail/logValidation
=== RUN   TestAccCloudTrail_serial/Trail/eventSelector
=== RUN   TestAccCloudTrail_serial/Trail/migrateV0
    trail_test.go:817: Step 1/2 error: Check failed: Check 4/4 error: aws_cloudtrail.test: Attribute 'id' expected "tf-acc-test-1052551585322808390", got "arn:aws:cloudtrail:us-west-2:100180206982:trail/tf-acc-test-1052551585322808390"
=== RUN   TestAccCloudTrail_serial/Trail/basic
=== RUN   TestAccCloudTrail_serial/Trail/cloudwatch
=== RUN   TestAccCloudTrail_serial/Trail/snsTopicNameBasic
--- FAIL: TestAccCloudTrail_serial (760.78s)
    --- FAIL: TestAccCloudTrail_serial/Trail (760.78s)
        --- PASS: TestAccCloudTrail_serial/Trail/enableLogging (59.34s)
        --- PASS: TestAccCloudTrail_serial/Trail/snsTopicNameAlternateRegion (32.59s)
        --- PASS: TestAccCloudTrail_serial/Trail/tags (54.54s)
        --- PASS: TestAccCloudTrail_serial/Trail/eventSelectorDynamoDB (33.01s)
        --- PASS: TestAccCloudTrail_serial/Trail/insightSelector (70.45s)
        --- PASS: TestAccCloudTrail_serial/Trail/disappears (24.99s)
        --- PASS: TestAccCloudTrail_serial/Trail/globalServiceEvents (24.80s)
        --- PASS: TestAccCloudTrail_serial/Trail/multiRegion (54.32s)
        --- SKIP: TestAccCloudTrail_serial/Trail/organization (0.79s)
        --- PASS: TestAccCloudTrail_serial/Trail/kmsKey (26.18s)
        --- PASS: TestAccCloudTrail_serial/Trail/eventSelectorExclude (59.07s)
        --- PASS: TestAccCloudTrail_serial/Trail/advancedEventSelector (25.46s)
        --- PASS: TestAccCloudTrail_serial/Trail/logValidation (39.70s)
        --- PASS: TestAccCloudTrail_serial/Trail/eventSelector (87.69s)
        --- FAIL: TestAccCloudTrail_serial/Trail/migrateV0 (22.23s)
        --- PASS: TestAccCloudTrail_serial/Trail/basic (43.39s)
        --- PASS: TestAccCloudTrail_serial/Trail/cloudwatch (59.17s)
        --- PASS: TestAccCloudTrail_serial/Trail/snsTopicNameBasic (43.07s)
FAIL
FAIL    github.com/hashicorp/terraform-provider-aws/internal/service/cloudtrail 761.014s
FAIL
make: *** [GNUmakefile:616: testacc] Error 1

$

[github-actions]

Community Note

Voting for Prioritization

• Please vote on this pull request by adding a 👍 reaction to the original post to help the community and maintainers prioritize this pull request.
• Please see our prioritization guide for information on how we prioritize.
• Please do not leave "+1" or other comments that do not add relevant new information or questions, they generate extra noise for issue followers and do not help prioritize the request.

For Submitters

• Review the contribution guide relating to the type of change you are making to ensure all of the necessary steps have been taken.
• For new resources and data sources, use skaff to generate scaffolding with comments detailing common expectations.
• Whether or not the branch has been rebased will not impact prioritization, but doing so is always a welcome surprise.