Restore the following:

* Box shadow for screen options/help tabs focus state.
* Text shadow on the about screen badge to match the text shadow in the graphic itself.
* Border for credits screen gravatars, in place of the previous box shadow.

props nacin. see #23415.


git-svn-id: https://core.svn.wordpress.org/trunk@23409 1a063a9b-81f0-0310-95a4-ce76da25c4cd