Merge branch '419829-require-last-fetched-at-notes' into 'master'

Require last_fetched_at in notes polling endpoint

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/127763



Merged-by: Aleksei Lipniagov <alipniagov@gitlab.com>
Approved-by: Aditya Tiwari <atiwari@gitlab.com>
Approved-by: Aleksei Lipniagov <alipniagov@gitlab.com>
Reviewed-by: Heinrich Lee Yu <heinrich@gitlab.com>
Reviewed-by: Aleksei Lipniagov <alipniagov@gitlab.com>
Co-authored-by: Heinrich Lee Yu <heinrich@gitlab.com>