Manually corrected user online beta meeting example file

Author: timayabi2020

src/CloudCommunications/beta/examples/Get-MgBetaUserOnlineMeeting.md

@@ -3,6 +3,7 @@
 ```powershell
 Import-Module Microsoft.Graph.Beta.CloudCommunications
 
+# A UPN can also be used as -UserId.
 Get-MgBetaUserOnlineMeeting -UserId $userId -Filter "joinMeetingIdSettings/joinMeetingId eq '1234567890'"
 ```
 This example shows how to use the Get-MgBetaUserOnlineMeeting Cmdlet.