Fix dropdowns

Summary:
Fix/Resurrect the dropdowns on these pages using the new drop lib

Fixes
- Filter by Roles dropdown on Manage Users page (small screens)
- Actions dropdown on Manage Users page (small screens)
- Change Role dropdown on bulk action bar on Manage Users page
- Actions dropdown on Manage Tags page (small screens)
- Filter by Box on Messages page (small screens)
- Actions dropdowns on each message on Messages page (small screens)

Test Plan: Try each dropdown described above. Try performing the same actions in small screen and large screen modes.

Reviewers: rjmackay, shadowhand

Reviewed By: shadowhand

Maniphest Tasks: T835

Differential Revision: https://phabricator.ushahidi.com/D385