Fixed some HAML errors on milestone#show
What does this MR do?
The issuable row had a HAML error that was causing it to not render correctly. The panel header also had 2 counts rather than 1 which led to mis-leading numbers.
Screenshots (if relevant)
Before:
After:
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/26799 and https://gitlab.com/gitlab-org/gitlab-ce/issues/26772.