Issue #3453320 by timurtripp: [10.3 regression] CKEditor 5 renamed CSS...

Issue #3453320 by timurtripp: [10.3 regression] CKEditor 5 renamed CSS variable causing CKEditor dialogs to fail to appear above jQuery UI dialogs

(cherry picked from commit 70383032)

core/modules/ckeditor5/css/ckeditor5.dialog.fix.css

 .ui-dialog ~ .ck-body-wrapper {
-  --ck-z-modal: 1261;
+  --ck-z-panel: 1261;
 }