fix(app): Add condition to enqueue script from transcoder

Enqueue script only if rtMedia class is exists. This script add some UI changes to rtMedia component, when it is used with transcoder.

admin/rt-transcoder-functions.php

@@ -811,7 +811,7 @@ function rtt_enqueue_frontend_scripts() {
 	$file_to_use = 'public-assets/js/build/transcoder.min.js';
 
 	$file = path_join( RT_TRANSCODER_PATH, $file_to_use );
-	if ( file_exists( $file ) ) {
+	if ( file_exists( $file ) && class_exists( 'RTMedia' ) ) {
 		wp_enqueue_script( 'rt-transcoder-front-js', RT_TRANSCODER_URL . $file_to_use, array( 'jquery', 'rtmedia-backbone' ), filemtime( $file ), true );
 
 		$rest_url_prefix = get_site_url() . '/' . rest_get_url_prefix();