Extend `PyBundledModule` with `extension.BundledModule`

[zhenyan-zhang-meta]

Context

This issue is a step of #9638 and a sequel of #10375.

In #9638, we want to have extension.Module as the single source of implementation in pybindings, which means that pybindings.PyModule should use extension.Module rather than its own pybindings.Module.

Proposal

Now that we have extension.BundledModule ready, we want to test it out by having our existing PyBundledModule to extend it, and let verify_result_with_bundled_expected_output to use it, so that we can test out the whole thing with https://github.com/pytorch/executorch/blob/fb45e19055a92d2a91a4d4b7008e135232cbb14b/devtools/bundled_program/test/test_end2end.py