Add userPrincipalName to attendanceRecord

Add the userPriccipalName to the response body in an attendanceRecord, just like emailAddress is now.

https://docs.microsoft.com/en-us/graph/api/resources/attendancerecord?view=graph-rest-beta

This will allow an alternative way to identify users.

The attendanceRecord will then look something like this:

{ 
    "userPrincipalName": "String", 
    "emailAddress": "String", 
    "totalAttendanceInSeconds": "Int32", 
    "role": "String(None|Attendee|Presenter|Organizer)", 
    "identity": {"@odata.type": "#microsoft.graph.identity"}, 
    "attendanceIntervals": [{"@odata.type": "#microsoft.graph.attendanceInterval"}] 
}