Customize: Hide expansion arrows in Customizer's available widgets list.

Fixes regression introduced by [42794].

Props dlh.
See #40677.
Fixes #43983.


git-svn-id: https://develop.svn.wordpress.org/trunk@43244 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/css/customize-widgets.css

@@ -235,6 +235,11 @@
 	width: auto !important;
 }
 
+/* Keep rule that is no longer necessary on widgets.php. */
+#available-widgets .widget-action {
+	display: none;
+}
+
 .ios #available-widgets {
 	transition: left 0s;
 }