Fix #19916. Crash when changing language (#19945)

Issue caused by the unload image function not resetting the image id back to invalid. Also noticed that water wasn't correctly cleaning up.

Fix #19918, #19926, #19927, #19928, #19929, #19931

src/openrct2/object/Object.cpp

@@ -197,6 +197,7 @@ void Object::UnloadImages()
     if (_baseImageId != ImageIndexUndefined)
     {
         GfxObjectFreeImages(_baseImageId, GetImageTable().GetCount());
+        _baseImageId = ImageIndexUndefined;
     }
 }