Media Grid: Fix escape key sometimes failing to close details modal.

Fix an issue where the escape key would no longer close the attachment details modal after attempting to navigate over the navigation boundaries (by clicking the left arrow key on the first media item or clicking the right arrow key on the last media item). Remove a focus blur which caused the underlying Backbone View to not receive the 'keydown' event.

Props subrataemfluence, afercia.
Fixes #42180.

Built from https://develop.svn.wordpress.org/trunk@41856


git-svn-id: http://core.svn.wordpress.org/trunk@41690 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/js/media-grid.js

@@ -795,7 +795,6 @@ EditAttachments = MediaFrame.extend(/** @lends wp.media.view.MediaFrame.EditAtta
 	 */
 	previousMediaItem: function() {
 		if ( ! this.hasPrevious() ) {
-			this.$( '.left' ).blur();
 			return;
 		}
 		this.trigger( 'refresh', this.library.at( this.getCurrentIndex() - 1 ) );
@@ -807,7 +806,6 @@ EditAttachments = MediaFrame.extend(/** @lends wp.media.view.MediaFrame.EditAtta
 	 */
 	nextMediaItem: function() {
 		if ( ! this.hasNext() ) {
-			this.$( '.right' ).blur();
 			return;
 		}
 		this.trigger( 'refresh', this.library.at( this.getCurrentIndex() + 1 ) );

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-beta2-41855';
+$wp_version = '4.9-beta2-41856';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.