Media Grid: Ignore user setting for `content`.

fixes #29034.
Built from https://develop.svn.wordpress.org/trunk@29305


git-svn-id: http://core.svn.wordpress.org/trunk@29087 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fix jshint errors introduced in [29284] and [29299].
Built from https://develop.svn.wordpress.org/trunk@29306


git-svn-id: http://core.svn.wordpress.org/trunk@29088 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media Grid: Align "Apply" button on small screens.

fixes #28903.
Built from https://develop.svn.wordpress.org/trunk@29307


git-svn-id: http://core.svn.wordpress.org/trunk@29089 1a063a9b-81f0-0310-95a4-ce76da25c4cd