Quick/Bulk Edit: Update focus color on inline edit panel.

Use admin theme variables to set the inline edit wrapper focus border.

Props hmbashar, joedolson, huzaifaalmesbah, mukesh27, shailu25, audrasjb, rahultank, manhar, ozgursar.
Fixes #64757.

git-svn-id: https://develop.svn.wordpress.org/trunk@61851 602fd350-edb4-49c9-b593-d223f7449a82