🎨 Design: Add comment and approval as part of code review (batch comments)

Pending comments counter should move to Pending comments dropup
Approve merge request should default to unchecked
Submitting review through one of the Submit review buttons on comments should automatically submit the review as usual
Any input/choice in dropup should be saved if user closes it or leaves page
When this is implemented- the first time a user opens the new dropup, an alert should appear highlighting quick action functionality. Once this is closed, it should never reappear.
Comment textarea should be in focus when dropup appears