Disable beta for authenticator_groups_config

[kir4h]

This PR makes authenticator_groups_config available to non beta clusters (through authenticator_security_group variable), since the option is not marked as beta anymore by the upstream provider (https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/container_cluster#private_cluster_config).

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[kir4h]

@googlebot I signed it!

[comment-bot-dev]

Thanks for the PR! 🚀
✅ Lint checks have passed.

[kir4h]

Any chance of getting permissions to check cloud build logs and see what is failing?

[morgante]

Errors look unrelated.