Accessibility: Media: Fix the Image Editor mismatching keyboard focus order...

Accessibility: Media: Fix the Image Editor mismatching keyboard focus order and visual reading order.

Swaps the DOM order of the two main columns within the admin Image Editor.

When the sequence in which content is presented affects its meaning and the navigation sequences affect meaning or operation, visual order and DOM order must match. See WCAG 2.1 Success Criterion 1.3.2 Meaningful Sequence and Success Criterion 2.4.3 Focus Order.

Props sabernhardt, anevins, audrasjb, afercia.
Fixes #47136.

Built from https://develop.svn.wordpress.org/trunk@48265


git-svn-id: https://core.svn.wordpress.org/trunk@48034 1a063a9b-81f0-0310-95a4-ce76da25c4cd