Appearance Themes: Don't show theme actions if the current theme doesn't support menus or widgets.

props MikeHansenMe.
fixes #25949.

git-svn-id: https://develop.svn.wordpress.org/trunk@26335 602fd350-edb4-49c9-b593-d223f7449a82
Revert property change in [26335].

git-svn-id: https://develop.svn.wordpress.org/trunk@26336 602fd350-edb4-49c9-b593-d223f7449a82