qt ConfirmTxDialog: word-wrap error message text

e.g. this text:
"This transaction requires a higher fee, or it will not be propagated by your current server. Try to raise your transaction fee, or use a server with a lower relay fee."
is too long for a single line.

electrum/gui/kivy/uix/dialogs/confirm_tx_dialog.py

@@ -10,7 +10,6 @@ from kivy.uix.label import Label
 from kivy.uix.widget import Widget
 from kivy.clock import Clock
 
-from electrum.simple_config import FEERATE_WARNING_HIGH_FEE, FEE_RATIO_HIGH_WARNING
 from electrum.gui.kivy.i18n import _
 from electrum.plugin import run_hook
 from electrum.util import NotEnoughFunds

electrum/gui/qt/confirm_tx_dialog.py

@@ -33,11 +33,10 @@ from electrum.i18n import _
 from electrum.util import NotEnoughFunds, NoDynamicFeeEstimates
 from electrum.plugin import run_hook
 from electrum.transaction import Transaction, PartialTransaction
-from electrum.simple_config import FEERATE_WARNING_HIGH_FEE, FEE_RATIO_HIGH_WARNING
 from electrum.wallet import InternalAddressCorruption
 
 from .util import (WindowModalDialog, ColorScheme, HelpLabel, Buttons, CancelButton,
-                   BlockingWaitingDialog, PasswordLineEdit)
+                   BlockingWaitingDialog, PasswordLineEdit, WWLabel)
 
 from .fee_slider import FeeSlider, FeeComboBox
 
@@ -166,8 +165,7 @@ class ConfirmTxDialog(TxEditor, WindowModalDialog):
         grid.addWidget(self.fee_slider, 5, 1)
         grid.addWidget(self.fee_combo, 5, 2)
 
-        self.message_label = QLabel(self.default_message())
-        self.message_label.setTextInteractionFlags(Qt.TextSelectableByMouse)
+        self.message_label = WWLabel(self.default_message())
         grid.addWidget(self.message_label, 6, 0, 1, -1)
         self.pw_label = QLabel(_('Password'))
         self.pw_label.setVisible(self.password_required)