Fix invalid invocation of `get_class_loader`.
Fix invalid invocation of `get_class_loader`.

The call was made on a `Godot` instance instead of an `Activity` instance.

(cherry picked from commit 2d492ff8ba8b9fe1acb1786007d797659cc1ee3e)

ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot