replace resolve_path with Module.get_submodule

[norabelrose]

we can use Module.get_submodule for this, combined with the PreTrainedModel.base_model property to unwrap wrapped models

[SrGonao]

Ok I'm actually super confused with this issue.

module.get_submodule gets us the module that has a specific name. Lucia is using resolve_path to get a list of strings that will then be assembled to be the key in the dictionary that has the encoder functions of the sparse coders.

I'm confused because:

• We don't need to use .get_submodule for anything.
• I'm not sure why we need to resolve_path now that we removed NNsight.

Not having resolve_path still runs e2e.py. Was there a particular case where it was usefull? Really need to know why you added it @luciaquirke