Issue #3577367: Add caching to sortedGroups() and sortedTags() methods

Add instance-level caching to prevent excessive sorting operations during form rendering. The sorted tag and group definitions don't change during a single request, so results can be cached after the first computation.

This addresses a performance regression exposed by Drupal core 10.5.5/10.5.6 changes to entity revision queries.

Closes #3577367