URL encryption modified for ShowAllOperators

In the control ShowAllOperators the call to pzEncryptURLActionString was introduced to encrypt URLs to avoid hijacking. The content of the URL relied on the pxRequestor.pxWorkGroup property which was resolved using pega:reference tags. This approach worked in versions below 8.x, but in higher versions the tags were not resolved at runtime and results were not displayed. To resolve this, the requestorWorkGroup will be treated as string and passed as parameter instead of using pega:reference tags.