device page: disable resize button if there are no zones

I have an unsupported Asus GPU which shows up as a device but doesn't
have any zone configured. Clicking on the Resize button leads to an
out-of-bounds read in the empty `zones` vector to `zones[-1]` (default
value of the QComboBox property).

The fix is to entirely disable the button when we're disabling the zones
box.

qt/OpenRGBDevicePage.cpp

@@ -703,6 +703,7 @@ void Ui::OpenRGBDevicePage::UpdateModeUi()
                 else
                 {
                     ui->ZoneBox->setDisabled(1);
+                    ui->ResizeButton->setEnabled(false);
                 }
 
                 for (std::size_t i = 0; i < device->zones.size(); i++)