Enable api_caching_rate_limit_branches by default

Changelog: performance

changelogs/unreleased/grape-action-caching-default.yml

+---
+title: Apply rate-limit cache to branches endpoint
+merge_request: 61723
+author:
+type: performance

config/feature_flags/development/api_caching_rate_limit_branches.yml

@@ -5,4 +5,4 @@ rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/330876
 milestone: '13.12'
 type: development
 group: group::source code
-default_enabled: false
+default_enabled: true