Update release search filter feature flag to be enabled by default
What does this MR do?
Updates the :release_search_filter
flag to be enabled by default.
This flag hides all functionality related to the new release:
search filter being developed in #32632 (closed).
Why?
This flag should be enabled by default as the intention is to ship this feature as part of %12.5 both to self-managed customers as well as GitLab.com. According to https://docs.gitlab.com/ee/development/feature_flags/process.html#including-a-feature-behind-feature-flag-in-the-final-release:
In order to build a final release and present the feature for self-hosted users, the feature flag should be at least defaulted to on.
Changelog
This MR does not contain a changelog as the associated changelogs have already been included (perhaps mistakenly) in other MRs related to this feature. In the future, I'll instead include the changelog with the MR that actually enables the feature.