resource/aws_cloudwatch_metric_alarm: Validate alarm actions

[tkbky]

Fixes #6092

Changes proposed in this pull request:

• Validate that alarm_actions is a valid ARN.

Output from acceptance testing:

$ make testacc TESTARGS='-run=TestAccAWSCloudWatchMetricAlarm'

TF_ACC=1 go test ./... -v -run=TestAccAWSCloudWatchMetricAlarm -timeout 120m
?   	github.com/terraform-providers/terraform-provider-aws	[no test files]
=== RUN   TestAccAWSCloudWatchMetricAlarm_importBasic
--- PASS: TestAccAWSCloudWatchMetricAlarm_importBasic (31.49s)
=== RUN   TestAccAWSCloudWatchMetricAlarm_basic
--- PASS: TestAccAWSCloudWatchMetricAlarm_basic (28.72s)
=== RUN   TestAccAWSCloudWatchMetricAlarm_datapointsToAlarm
--- PASS: TestAccAWSCloudWatchMetricAlarm_datapointsToAlarm (26.34s)
=== RUN   TestAccAWSCloudWatchMetricAlarm_treatMissingData
--- PASS: TestAccAWSCloudWatchMetricAlarm_treatMissingData (45.47s)
=== RUN   TestAccAWSCloudWatchMetricAlarm_evaluateLowSampleCountPercentiles
--- PASS: TestAccAWSCloudWatchMetricAlarm_evaluateLowSampleCountPercentiles (46.52s)
=== RUN   TestAccAWSCloudWatchMetricAlarm_extendedStatistic
--- PASS: TestAccAWSCloudWatchMetricAlarm_extendedStatistic (25.65s)
=== RUN   TestAccAWSCloudWatchMetricAlarm_missingStatistic
--- PASS: TestAccAWSCloudWatchMetricAlarm_missingStatistic (8.36s)
PASS
ok  	github.com/terraform-providers/terraform-provider-aws/aws	212.588s
...

[bflad]

LGTM, thanks @tkbky! 🚀

--- PASS: TestAccAWSCloudWatchMetricAlarm_missingStatistic (1.96s)
--- PASS: TestAccAWSCloudWatchMetricAlarm_datapointsToAlarm (4.13s)
--- PASS: TestAccAWSCloudWatchMetricAlarm_extendedStatistic (4.16s)
--- PASS: TestAccAWSCloudWatchMetricAlarm_basic (4.26s)
--- PASS: TestAccAWSCloudWatchMetricAlarm_importBasic (4.61s)
--- PASS: TestAccAWSCloudWatchMetricAlarm_treatMissingData (6.98s)
--- PASS: TestAccAWSCloudWatchMetricAlarm_evaluateLowSampleCountPercentiles (7.35s)

[bflad]

This has been released in version 1.41.0 of the AWS provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

[prasanthsurapaneni]

. we are using cloudwatch alarm for setting ec2 recovery and the validation for the alarm action is failing across the board. This has impaired our production instances with entire workspaces getting errored out. Please look into this.

[bflad]

@prasanthsurapaneni please see #6203

[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!