fix: Correct encryption configuration enable logic; avoid creating Auto Mode policy when Auto Mode is not enabled

[bryantbiggs]

Description

• Correct encryption configuration enable logic to allow users to disable CMK encryption
• Avoid creating Auto Mode policy when Auto Mode is not enabled

Motivation and Context

• Closes fix: Local enable_encryption_config still reads true even when toggled off #3438
• Ref fix: Move encryption_config default for resources out of type definition and to default variable value to allow disabling encryption #3436
• Ref v21: encryption cannot be turned off with encryption config. #3435

Breaking Changes

• No

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 PR is included in version 21.0.4 🎉

[tluck]

something is not right here with enable_encryption_config

• if one wants to use an aws owned kms key and not a customer managed key...

locals {
  create = var.create && var.putin_khuylo

  account_id = try(data.aws_caller_identity.current[0].account_id, "")
  partition  = try(data.aws_partition.current[0].partition, "")

  role_arn = try(aws_iam_role.this[0].arn, var.iam_role_arn)

  create_outposts_local_cluster = var.outpost_config != null
  enable_encryption_config      = var.encryption_config != null && !local.create_outposts_local_cluster

  auto_mode_enabled = try(var.compute_config.enabled, false)
}

with this line
enable_encryption_config = var.encryption_config != null && !local.create_outposts_local_cluster

enable_encryption seems to become true by default - since the default encryption_config (in variables.tf) is an empty object and not null

edit/setting default encryption_config = null vs {} in module variables .tf (like outpost_config) - then it works as expected (and like v5.)

[bryantbiggs]

We're not triaging unless there is a reproduction