Widgets: Fix deferred rendering of controls for media widgets until container element fully expands.

Adds omitted call to `renderWhenAnimationDone()` which was missed when this code was copied from the Text widget.

Amends [40656].
See #40750.

Built from https://develop.svn.wordpress.org/trunk@40660


git-svn-id: http://core.svn.wordpress.org/trunk@40523 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/widgets/media-widgets.js

@@ -1065,6 +1065,7 @@ wp.mediaWidgets = ( function( $ ) {
 				widgetControl.render();
 			}
 		};
+		renderWhenAnimationDone();
 
 		/*
 		 * Note that the model and control currently won't ever get garbage-collected

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-alpha-40659';
+$wp_version = '4.8-alpha-40660';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.