Post Edit Modal, fixes T366

Summary:
* fixes T366

* removes categories from `EditPost` modal

* adjusts `post-header h5` line height to accommodate for multiple lines
	* adjusts `.post-actions-admin` margin top to compensate

Test Plan: * confirm @rjmackays suggested changes from T366

Reviewers: shadowhand, rjmackay

Reviewed By: shadowhand, rjmackay

Subscribers: srutto, dkobia

Maniphest Tasks: T366

Differential Revision: https://phabricator.ushahidi.com/D202