Media: Use consistent mirroring check in media views.

Change the mirroring property verification method to be consistent with other usages across models and attachments, since we don't care whether it's assigned directly on inherited.

Props MMDeveloper, SergeyBiryukov.
Fixes #53856.

Built from https://develop.svn.wordpress.org/trunk@52806


git-svn-id: http://core.svn.wordpress.org/trunk@52395 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/js/media-views.js

@@ -2116,7 +2116,7 @@ AttachmentsBrowser = View.extend(/** @lends wp.media.view.AttachmentsBrowser.pro
 			mediaFoundHasMoreResultsMessage = __( 'Number of media items displayed: %d. Scroll the page for more results.' );
 		}
 
-		if ( this.collection.hasOwnProperty('mirroring') && this.collection.mirroring.args.s ) {
+		if ( this.collection.mirroring && this.collection.mirroring.args.s ) {
 			count = this.collection.length;
 
 			if ( 0 === count ) {

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.0-alpha-52805';
+$wp_version = '6.0-alpha-52806';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.