TinyMCE: Fix keyboard navigation when the dfw button is present but hidden. Ensure that button is added last in the DOM to match where it appears visually.

Props afercia, azaozz.
Fixes #46640.

git-svn-id: https://develop.svn.wordpress.org/trunk@45172 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/css/editor.css

@@ -1269,6 +1269,13 @@ i.mce-i-wp_code:before {
 	position: absolute;
 	top: 0;
 	right: 0;
+}
+
+.mce-toolbar .mce-btn-group .mce-btn.mce-wp-dfw {
+	margin: 7px 7px 0 0;
+}
+
+.qt-dfw {
 	margin: 5px 5px 0 0;
 }