Themes: Refine how we display the current theme.

props shaunandrews, kwight, matveb.
see #26003.


git-svn-id: https://develop.svn.wordpress.org/trunk@26681 602fd350-edb4-49c9-b593-d223f7449a82
More consistent vertical alignment of the .awaiting-mod/new updates indicator. See #25858.

git-svn-id: https://develop.svn.wordpress.org/trunk@26682 602fd350-edb4-49c9-b593-d223f7449a82