throw instead of segfault with invalid args in pybindings

[pytorchbot]

Summary: Fixed some Error() call sites and added better checking on the method name

Reviewed By: larryliu0820

Differential Revision: D63547425

closes #5648

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/6108

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❌ 2 New Failures

As of commit 78990e9 with merge base eecf74f ():

NEW FAILURES - The following jobs have failed:

• Build documentation / build (buck2) / Build doc (gh)
  ##[error]No files were found with the provided path: /home/ec2-user/actions-runner/_work/_temp/artifacts/. No artifacts will be uploaded.
• pull / unittest-arm (buck2) / linux-job (gh)
  ../../dev/ops/test_add.py::TestSimpleAdd::test_add2_tosa_BI_4

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[jackzhxng]

Seems safe but need to fix tests

[dbort]

The bulk of this was squashed into cherrypick #6151. Rebased on top of that to show the differences, which aren't critical for the release branch. Closing this commit without merging.