(trivial) qt main_window: rm unnecessary indendation

electrum/gui/qt/main_window.py

@@ -1419,7 +1419,8 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
                 self.fee_e.setAmount(None)
             self.not_enough_funds = False
             self.statusBar().showMessage('')
-        else:
+            return
+
         outputs, fee_estimator, tx_desc, coins = self.read_send_tab()
         if not outputs:
             _type, addr = self.get_payto_or_dummy()