Update Set-OwaMailboxPolicy.md

Confirmed with Engineering and in lab, CalendarEnabled parameter is valid for Exchange Online as well and is not Exchange OnPremise only.
Updating doc

Author: qaehtesh

exchange/exchange-ps/exchange/Set-OwaMailboxPolicy.md

@@ -561,7 +561,6 @@ Accept wildcard characters: False
 ```
 
 ### -CalendarEnabled
-This parameter is functional only in on-premises Exchange.
 
 The CalendarEnabled parameter specifies whether to enable or disable the calendar in Outlook Web App. Valid values are: