qml: reset _key in QEInvoice on clear()

Author: accumulator

electrum/gui/qml/qeinvoice.py

@@ -485,6 +485,7 @@ def fromResolvedPaymentIdentifier(self, resolved_pi: PaymentIdentifier) -> None:
         self.amountOverride = QEAmount()
         if resolved_pi:
             assert not resolved_pi.need_resolve()
+            self.clear()
             self.validateRecipient(resolved_pi)
 
     @pyqtProperty('QVariantMap', notify=lnurlRetrieved)
@@ -510,6 +511,7 @@ def busy(self):
     @pyqtSlot()
     def clear(self):
         self.setInvoiceType(QEInvoice.Type.Invalid)
+        self._key = None
         self._lnurlData = None
         self._offerData = None
         self.canSave = False