Prevent scrolling beneath modals on mobile devices by removing overflow from #wpwrap when a modal is open.

Fixes #29909
Props avryl


git-svn-id: https://develop.svn.wordpress.org/trunk@30707 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/css/common.css

@@ -223,6 +223,11 @@ body.modal-open {
 	overflow: hidden;
 }
 
+body.mobile.modal-open #wpwrap {
+	overflow: hidden;
+	height: 100%;
+}
+
 iframe,
 img {
 	border: 0;