Merge branch '515319-cngo-show-new-comment' into 'master'

Add comment to cache when submitting a comment on a work item

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/180268



Merged-by: Natalia Tepluhina <ntepluhina@gitlab.com>
Approved-by: Natalia Tepluhina <ntepluhina@gitlab.com>
Co-authored-by: Coung Ngo <cngo@gitlab.com>