Fix new post->tags transition
Fix new post->tags transition

refs #6483, closes #6541
- removes unloading of all tags when entering the tags screen. Tags list will now function similarly to the content list where already-loaded tags are visible immediately.

Fixes #6483 because it prevents selectize's data being changed out from underneath it before it's destroyed.

dbalders/Ghost-Admin,airycanon/Ghost-Admin,dbalders/Ghost-Admin,TryGhost/Ghost-Admin,airycanon/Ghost-Admin,kevinansfield/Ghost-Admin,acburdine/Ghost-Admin,JohnONolan/Ghost-Admin,JohnONolan/Ghost-Admin,TryGhost/Ghost-Admin,kevinansfield/Ghost-Admin,acburdine/Ghost-Admin