Properly render the image details modal when the image references an invalid attachment.

props gcorne.
fixes #27537.

Built from https://develop.svn.wordpress.org/trunk@27756


git-svn-id: http://core.svn.wordpress.org/trunk@27593 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Customizer: Improve accessibility.

Prevent the form only from saving when enter is pressed on a select element or an input, which hasn't the button type.

props westonruter, ocean90.
fixes #26633.
Built from https://develop.svn.wordpress.org/trunk@27757


git-svn-id: http://core.svn.wordpress.org/trunk@27594 1a063a9b-81f0-0310-95a4-ce76da25c4cd