Merge branch 'determine-sharding-key-feature-category-feature_flags' into 'master'

Add sharding keys for feature_flags

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/142506



Merged-by: Leonardo da Rosa <ldarosa@gitlab.com>
Approved-by: Hunter Stewart <hustewart@gitlab.com>
Co-authored-by: Dylan Griffith <dyl.griffith@gmail.com>