Widget Customizer: Add a label to widget search.

props SergeyBiryukov.
fixes #27590.
Built from https://develop.svn.wordpress.org/trunk@27860


git-svn-id: http://core.svn.wordpress.org/trunk@27691 1a063a9b-81f0-0310-95a4-ce76da25c4cd
MEjs has been fixed upstream: https://github.com/johndyer/mediaelement/commit/1a75559c9d9ada344fee7a6f5f08ccc1e4b0fbfa
No more infinite loop.

This restores MediaElement to a clean build: `2.14.0`.

Fixes #27582. 
Thanks to jeremyfelt for tracking this down.


Built from https://develop.svn.wordpress.org/trunk@27861


git-svn-id: http://core.svn.wordpress.org/trunk@27692 1a063a9b-81f0-0310-95a4-ce76da25c4cd