fix(pencil): Invalid client token handling

Author: alexivsn

src/events/sdk-event.ts

@@ -36,7 +36,7 @@ export default class SDKEvent implements IEvent {
     const context = event.context || {};
     const decryptedToken = decrypt(context?.clientToken, options.apiKey);
     Logger.debug('Decrypted client token', decryptedToken);
-    const parsedToken = JSON.parse(decryptedToken) || {};
+    const parsedToken = decryptedToken && JSON.parse(decryptedToken) || {};
     Logger.debug('Parsed client token:', parsedToken);
 
     const user: any = event.userTraits || {};