fix: Ensure that custom KMS key is not created if encryption is not enabled, support computed values in cluster name

[bryantbiggs]

Description

• Ensure that custom KMS key is not created if encryption is not enabled
• Avoid throwing an index error when users provide their own custom launch template instead of the module creating a custom launch template
• Support instances where a computed value is passed into the cluster name, such as using random provider resources

Motivation and Context

• Currently, you could end up with a custom KMS key that is not used by the cluster if encryption is disabled
• Allow users to pass in computed values as the cluster name without error
• Resolves Upgrade 18.x --> 19.x- create_kms_key Provision Error #2321
• Resolves Error: error creating KMS Key: MalformedPolicyDocumentException #2325

Breaking Changes

• The default KMS key alias for the cluster name will be re-created but this is generally a safe process since its just an identifier. Otherwise, no breaking changes

How Has This Been Tested?

• I have updated at least one of the examples/* to demonstrate and validate my change(s)
• I have tested and validated these changes using one or more of the provided examples/* projects
• I have executed pre-commit run -a on my pull request

[antonbabenko]

This issue has been resolved in version 19.0.4 🎉

[github-actions]

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