qt: focus reason can't be None (fixes #8962)

Author: accumulator

electrum/gui/qt/paytoedit.py

@@ -199,7 +199,7 @@ def setText(self, text: str) -> None:
             self.line_edit.setText(text)
             self.text_edit.setText(text)
 
-    def setFocus(self, reason=None) -> None:
+    def setFocus(self, reason=Qt.OtherFocusReason) -> None:
         if self.multiline:
             self.text_edit.setFocus(reason)
         else: