Some checkboxes, e.g. main_window.warn_if_testnet became buggy with pyqt6:
looks like the stateChanged signal passes an int, not a Qt.CheckState.
(and note that Qt.CheckState is an Enum, not an IntEnum).
So `x == Qt.CheckState.Checked` would always evaluate to False.
```
def on_cb(_x):
print(f"heyheyhey. {_x=!r}, {Qt.CheckState.Checked=!r}, {cb.checkState()=!r}, {cb.isChecked()=!r}")
cb = QCheckBox("")
cb.stateChanged.connect(on_cb)
```
heyheyhey. x=2, Qt.CheckState.Checked=<CheckState.Checked: 2>, cb.checkState()=<CheckState.Checked: 2>, cb.isChecked()=True
heyheyhey. x=0, Qt.CheckState.Checked=<CheckState.Checked: 2>, cb.checkState()=<CheckState.Unchecked: 0>, cb.isChecked()=False
e05d2a5dbe