Enable `hash_based_cache_for_protected_branches` FF by default

Contributes to #368279

Changelog: added

config/feature_flags/development/hash_based_cache_for_protected_branches.yml

@@ -5,4 +5,4 @@ rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/368279
 milestone: '15.3'
 type: development
 group: group::source code
-default_enabled: false
+default_enabled: true