Get library categories for demo institute.

<br> <i>Replaces "AVRCMSService/External/AVRGetDemoLibraryCategories" service.</i> </br> <br> <b>AVRDemoId</b>: 1 (MagicLeap), 2 (Oculus), 3 (XR Library)</br>

{
  "avrDemoId": 3
}