While introducing the new drafts dropdown menu component, we also made
some changes to how the sidebar link works for Drafts. However, after
following user feedback and internal discussions we decided to revert
back to the shared link approach that combines My Posts and My Drafts.
This change adds a new dropdown trigger next to the "New Topic" button.
When clicked a menu will display a list of topic/post drafts that can be
clicked to resume the draft within the composer.
The "New Topic" button will no longer change text to show "Open Draft"
when a draft topic exists, it will still attempt to load the existing
draft if one exists (this will change later when we support multiple
drafts in a separate PR).
The "My Posts" link in desktop sidebar will now be "My Drafts" and only
appear when the current user has existing drafts.
