Remove unnecessary CSS overriding on Add Plugins screen.

props pavelevap.
fixes #29753.
Built from https://develop.svn.wordpress.org/trunk@29775


git-svn-id: http://core.svn.wordpress.org/trunk@29547 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media: disable multi-file uploading in iOS 7.x Safari as it prevents uploading of videos. Fixes #29602 for trunk.
Built from https://develop.svn.wordpress.org/trunk@29776


git-svn-id: http://core.svn.wordpress.org/trunk@29548 1a063a9b-81f0-0310-95a4-ce76da25c4cd