Login and Registration: Add white background to register screen notices.

This changeset backports the changes made to common notices to `login.css`.

Props juanfra, huzaifaalmesbah, shailu25, joedolson.
Fixes #64715.



git-svn-id: https://develop.svn.wordpress.org/trunk@61731 602fd350-edb4-49c9-b593-d223f7449a82

Author: audrasjb

src/wp-admin/css/login.css

@@ -66,6 +66,10 @@ p {
 	background-color: #eff9f1;
 }
 
+.login .notice {
+	background-color: #fff;
+}
+
 /* Match border color from common.css */
 .login .notice-error {
 	border-left-color: #cc1818;