Toolbar: Reset box-shadow on links.

This prevents any theme-added `box-shadow` styles from applying to the toolbar items.

Props sabernhardt, florianbrinkmann.
Fixes #40594.



git-svn-id: https://develop.svn.wordpress.org/trunk@50847 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/css/admin-bar.css

@@ -54,6 +54,7 @@ html:lang(he-il) .rtl #wpadminbar * {
 	border: none;
 	text-decoration: none;
 	background: none;
+	box-shadow: none;
 }
 
 #wpadminbar a:focus,