Fix JSHint errors introduced in [30120].

see #30193.
Built from https://develop.svn.wordpress.org/trunk@30123


git-svn-id: http://core.svn.wordpress.org/trunk@30123 1a063a9b-81f0-0310-95a4-ce76da25c4cd
JSHint after [30120].


Built from https://develop.svn.wordpress.org/trunk@30124


git-svn-id: http://core.svn.wordpress.org/trunk@30124 1a063a9b-81f0-0310-95a4-ce76da25c4cd
JSHint after [30124].

Built from https://develop.svn.wordpress.org/trunk@30125


git-svn-id: http://core.svn.wordpress.org/trunk@30125 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Customizer: Improve `ColorControl`'s `wpColorPicker` to update UI based on setting changes.

Update Twenty Fifteen's `colorScheme` control to properly interact with the API, using `wp.customize.control()` instead of traversing DOM for other controls' container elements and stop manually updating color control UIs.

props westonruter.
fixes #30031.
Built from https://develop.svn.wordpress.org/trunk@30126


git-svn-id: http://core.svn.wordpress.org/trunk@30126 1a063a9b-81f0-0310-95a4-ce76da25c4cd