Widgets: Style the Image Widget's link field as invalid when a bad URL is supplied.

Fixes issue where user may supply an invalid URL and be unable to save the widget on the Widgets admin screen without being told why.

Amends [41252].
See #41274.
Fixes #42488 for 4.9.

Built from https://develop.svn.wordpress.org/branches/4.9@42141


git-svn-id: http://core.svn.wordpress.org/branches/4.9@41972 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/css/widgets-rtl.css

@@ -154,7 +154,8 @@
 	top: 30px;
 }
 
-.media-frame #embed-url-field.invalid {
+.media-frame #embed-url-field.invalid,
+.media-widget-image-link > .link:invalid {
 	border: 1px solid #dc3232;
 }
 

wp-admin/css/widgets.css

@@ -154,7 +154,8 @@
 	top: 30px;
 }
 
-.media-frame #embed-url-field.invalid {
+.media-frame #embed-url-field.invalid,
+.media-widget-image-link > .link:invalid {
 	border: 1px solid #dc3232;
 }
 

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-RC2-42139';
+$wp_version = '4.9-RC2-42141';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.