Merge branch 'psi-instant-issue-discussions' into 'master'

Load linked discussions on issues instead of single note

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/177537



Merged-by: Simon Knox <simon@gitlab.com>
Approved-by: James Rushford <jrushford@gitlab.com>
Approved-by: Tomas Bulva <tbulva@gitlab.com>
Reviewed-by: Simon Knox <simon@gitlab.com>
Reviewed-by: James Rushford <jrushford@gitlab.com>