Added if webhook to stop 500 in webhook absence

lnbits/extensions/lnticket/crud.py

@@ -54,6 +54,7 @@ async def set_ticket_paid(payment_hash: str) -> Tickets:
         )
         
         ticket = await get_ticket(payment_hash)
+        if formdata.webhook:
             async with httpx.AsyncClient() as client:
                 try:
                     r = await client.post(