Sanity check $uploaderToggler in wp.media.view.UploaderInline.

This ensures `$uploaderToggler` exists before checking length so any views
extending or scripts accessing this view, won't encounter errors that stop execution.

See #41231.

Merges [41009] to the 4.8 branch.

Built from https://develop.svn.wordpress.org/branches/4.8@41010


git-svn-id: http://core.svn.wordpress.org/branches/4.8@40860 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/js/media-views.js

@@ -8227,13 +8227,13 @@ UploaderInline = View.extend({
 	},
 	show: function() {
 		this.$el.removeClass( 'hidden' );
-		if ( this.controller.$uploaderToggler.length ) {
+		if ( this.controller.$uploaderToggler && this.controller.$uploaderToggler.length ) {
 			this.controller.$uploaderToggler.attr( 'aria-expanded', 'true' );
 		}
 	},
 	hide: function() {
 		this.$el.addClass( 'hidden' );
-		if ( this.controller.$uploaderToggler.length ) {
+		if ( this.controller.$uploaderToggler && this.controller.$uploaderToggler.length ) {
 			this.controller.$uploaderToggler
 				.attr( 'aria-expanded', 'false' )
 				// Move focus back to the toggle button when closing the uploader.