Widgets: Improve the News dashboard widget no-js notice.

In the rare case this notice was displayed, it was unstyled. Uses the notice 
error style to make it prettier and consistent with other no-js notices.
Also, some CSS clean-up.

Fixes #40529.

Built from https://develop.svn.wordpress.org/trunk@40556


git-svn-id: http://core.svn.wordpress.org/trunk@40425 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/css/dashboard-rtl.css

@@ -308,19 +308,21 @@
 	padding: 0;
 }
 
-#dashboard_primary .widget-loading,
-#dashboard_primary .dashboard-widget-control-form {
+#dashboard_primary .widget-loading {
 	padding: 12px 12px 0;
+	margin-bottom: 1em !important; /* Needs to override `.postbox .inside > p:last-child` in common.css */
+}
+
+/* Notice when JS is off. */
+#dashboard_primary .inside .notice {
+	margin: 0;
 }
 
 body #dashboard-widgets .postbox form .submit {
 	margin: 0;
 }
 
-.dashboard-widget-control-form {
-	overflow: hidden;
-}
-
+/* Used only for configurable widgets. */
 .dashboard-widget-control-form p {
 	margin-top: 0;
 }

wp-admin/css/dashboard.css

@@ -308,19 +308,21 @@
 	padding: 0;
 }
 
-#dashboard_primary .widget-loading,
-#dashboard_primary .dashboard-widget-control-form {
+#dashboard_primary .widget-loading {
 	padding: 12px 12px 0;
+	margin-bottom: 1em !important; /* Needs to override `.postbox .inside > p:last-child` in common.css */
+}
+
+/* Notice when JS is off. */
+#dashboard_primary .inside .notice {
+	margin: 0;
 }
 
 body #dashboard-widgets .postbox form .submit {
 	margin: 0;
 }
 
-.dashboard-widget-control-form {
-	overflow: hidden;
-}
-
+/* Used only for configurable widgets. */
 .dashboard-widget-control-form p {
 	margin-top: 0;
 }