Promote granular personal access tokens to GA

What does this MR do and why?

Enable the granular_personal_access_tokens beta flag by default and promote the enforcement flag from wip to beta default enabled on so the feature is available on all offerings. Remove the beta badges from the token creation dropdown and form, drop the beta suffix from the Permissions Assistant agent, and update the documentation to reflect general availability.

Changelog: changed

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Related to #584414