Media: Disable 'Insert gallery' and 'Set featured image' if nothing is queued....

Media: Disable 'Insert gallery' and 'Set featured image' if nothing is queued. Converts selection toolbars to use the newer view manager. props koopersmith, fixes #22714.



git-svn-id: https://core.svn.wordpress.org/trunk@23024 1a063a9b-81f0-0310-95a4-ce76da25c4cd