Merge branch 'jm-send-zoekt-stop-indexing' into 'master'

Send stop indexing signal to zoekt nodes when critical watermark is exceeded

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/173167



Merged-by: Dmitry Gruzd <dgruzd@gitlab.com>
Approved-by: Arturo Herrero <arturo.herrero@gmail.com>
Approved-by: Dmitry Gruzd <dgruzd@gitlab.com>
Reviewed-by: GitLab Duo <gitlab-duo@gitlab.com>
Co-authored-by: John Mason <jmason@gitlab.com>
Co-authored-by: Arturo Herrero <arturo.herrero@gmail.com>