Merge branch '268053-update-adding-feature-flags-behaviour' into 'master'

Improve UX feedback when project deploy feature flags limit is reached

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/147446



Merged-by: Mark Florian <mflorian@gitlab.com>
Approved-by: Emily Bauman <ebauman@gitlab.com>
Approved-by: Laura Callahan <lmeckley@gitlab.com>
Approved-by: Mark Florian <mflorian@gitlab.com>
Reviewed-by: Mark Florian <mflorian@gitlab.com>
Reviewed-by: Laura Callahan <lmeckley@gitlab.com>
Co-authored-by: Anton Kalmykov <anton.kalmykov@proton.me>