Enable "Legacy Authorization" by default when creating a Cluster on GCP

What does this MR do?

Enables "Legacy Authorization" by default when creating a cluster through CI / CD > Kubernetes

Why was this MR needed?

A "Legacy Authorization" disable prevents cluster applications (tiller, prometheus, etc) from being installed, which was causing to first create the cluster, and then manually change the "Legacy Authorization" option to be enabled.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests added for this feature/bug
• Review
  • Has been reviewed by Backend
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

Closes #41619 (closed)