Quick Tags; Trim Reblogs: Enable in communities

[marcustyphoon]

Description

This enables Quick Tags and Trim Reblogs on posts you authored/reblogged in communities.

See #1441.

Closes #1481.

Testing steps

At time of writing, I have a spare community with invite link tumblr.com/join/oki7cQsr.

• Confirm that Quick Tags/Trim Reblogs buttons appear, in the correct order, on posts you can edit in communities and on https://www.tumblr.com/communities.
• Confirm that Quick Tags/Trim Reblogs buttons do not appear, on posts you cannot edit in communities and on https://www.tumblr.com/communities.
• Confirm that the Quick Tags button functions.
• Confirm that the Trim Reblogs button functions and that the preview items appear correctly.
  --
• Confirm that the Quick Tags button appears and functions on non-community posts.
• Confirm that the Trim Reblogs button appears and functions on non-community posts.