qml: Remove key exist check in lnworker.payment_info

We don't use its result, and I've seen one occasion where a payment exists in history, but not in payment_info dict

electrum/gui/qml/qelnpaymentdetails.py

@@ -87,10 +87,6 @@ class QELnPaymentDetails(QObject):
             self._logger.error('wallet undefined')
             return
 
-        if self._key not in self._wallet.wallet.lnworker.payment_info:
-            self._logger.error('payment_hash not found')
-            return
-
         # TODO this is horribly inefficient. need a payment getter/query method
         tx = self._wallet.wallet.lnworker.get_lightning_history()[bfh(self._key)]
         self._logger.debug(str(tx))