Upgrade to Rails 7
Related epic: Rails 7.0.4 Upgrade (&7875 - closed)
Release notes: https://edgeguides.rubyonrails.org/7_0_release_notes.html
This MR contains the changes that should be merged along with the version bump. The changes that could be extracted into separate MRs have been merged separately.
This MR has been also cherry-picked and deployed on Staging and Production within the following experimentation: Rails 7 Upgrade rollout to SaaS and Self-Managed (gitlab-com/gl-infra&1029 - closed).
Edited by Igor Drozdov