Media: Fix broken media modal following [57688]

Fix undefined TypeError overlooked in [57688].

Props antpb, swissspidy, joedolson.
Fixes #58973.

git-svn-id: https://develop.svn.wordpress.org/trunk@57691 602fd350-edb4-49c9-b593-d223f7449a82

src/js/media/controllers/state.js

@@ -165,12 +165,16 @@ var State = Backbone.Model.extend(/** @lends wp.media.controller.State.prototype
 	_menu: function() {
 		var menu = this.frame.menu,
 			mode = this.get('menu'),
-			actionMenuItems = this.frame.menu.get('views'),
-			actionMenuLength = actionMenuItems ? actionMenuItems.views.get().length : 0,
+			actionMenuItems,
+			actionMenuLength,
 			view;
 
-		// Show action menu only if it is active and has more than one default element.
-		this.frame.$el.toggleClass( 'hide-menu', ! mode || actionMenuLength < 2 );
+		if ( this.frame.menu ) {
+			actionMenuItems = this.frame.menu.get('views'),
+			actionMenuLength = actionMenuItems ? actionMenuItems.views.get().length : 0,
+			// Show action menu only if it is active and has more than one default element.
+			this.frame.$el.toggleClass( 'hide-menu', ! mode || actionMenuLength < 2 );
+		}
 		if ( ! mode ) {
 			return;
 		}