R1:a76e91ea9ef6

Remove obsolete Dashboard panel methods with no callsites

Summary: Ref T13272. Since the move to EditEngine, these methods have no callsites.

Test Plan: `grep`

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13272

Differential Revision: https://secure.phabricator.com/D20484