Fix e49150f9ca: House picker crashes if selection is not available. (#14030)

This occurs because the extra invalidation in OnInit() also happens on construction, and too early.

Solution is to validate all instead of just position when invalidating in OnInit().

src/town_gui.cpp

@@ -1743,7 +1743,7 @@ struct BuildHouseWindow : public PickerWindow {
 
 	void OnInit() override
 	{
-		this->InvalidateData(PickerInvalidation::Position);
+		this->InvalidateData(PICKER_INVALIDATION_ALL);
 		this->PickerWindow::OnInit();
 	}