Regressions for assigning group milestone from ancestor
A few regressions (incomplete implementations) for https://gitlab.com/gitlab-org/gitlab-ce/issues/36862.
I found these regressions with this test issue: https://staging.gitlab.com/tanuki-group/fox-group/dog-project/issues/2
Quick action
I wasn't able to use the quick action to add the milestone. (But I could use the quick action to remove the milestone, after adding it in the sidebar.)
System note
The system note should render the milestone as a link to the milestone page. It doesn't do that currently.
Link in the sidebar
Once added, the milestone in the sidebar should be a link to the milestone page.
When you first link to the ancestor group milestone, the link is incorrect. It links to a nonexistent milestone in the current project. However, after you refresh the page, it links to the correct milestone.