Update util.ts

Fix undefined error in isRDLEmbed function. 

Raised exception on calling report page capture function.

Author: SanoLitch

src/util.ts

@@ -170,7 +170,7 @@ export function isSavedInternal(hpm: HttpPostMessage, uid: string, contentWindow
  * @returns {boolean}
  */
 export function isRDLEmbed(embedUrl: string): boolean {
-  return embedUrl.toLowerCase().indexOf("/rdlembed?") >= 0;
+  return embedUrl && embedUrl.toLowerCase().indexOf("/rdlembed?") >= 0;
 }
 
 /**
@@ -195,4 +195,4 @@ export function getRandomValue() {
   cryptoObj.getRandomValues(randomValueArray);
 
   return randomValueArray[0];
-}
+}