Customizer: fix logo cropping.

Address a failure in the customizer site logo cropping after r60031. Check to ensure library exists before the call to findWhere.

Follow up to r60031.

Props: domainsupport, joemcgill, joedolson, kawsar007, addweb-solution-pvt-ltd, mukesh27.

Fixes #63121.




git-svn-id: https://develop.svn.wordpress.org/trunk@60054 602fd350-edb4-49c9-b593-d223f7449a82

Author: adamsilverstein

src/js/media/views/toolbar.js

@@ -144,7 +144,7 @@ Toolbar = View.extend(/** @lends wp.media.view.Toolbar.prototype */{
 
 			var requires = button.options.requires,
 				disabled = false,
-				modelsUploading = ! _.isEmpty( library.findWhere(  { 'uploading': true } ) );
+				modelsUploading = library && ! _.isEmpty( library.findWhere( { 'uploading': true } ) );
 
 			// Prevent insertion of attachments if any of them are still uploading.
 			if ( selection && selection.models ) {