Intercept "no module named _pydantic_core" import errors and emit useful error

[davidhewitt]

We have notes at https://docs.pydantic.dev/latest/integrations/aws_lambda/#troubleshooting for debugging incorrect architecture installs.

I wonder if we should automate this step a little, by catching ImportError, and if it matches the problem condition for incorrect arch, emit a more helpful error message and maybe even link to the troubleshooting docs above.