polars-lts-cpu needed when running Jetstream locally on older CPU

[scholtzan]

I was trying to rerun an experiment locally but by calling Argo, but jetstream rerun simply got stuck indefinitely. It was showing this warning:
The following required CPU features were not detected ...

Installing polars-lts-cpu did resolve the issue. We might want to document this or simply just install this dependency?

┆Issue is synchronized with this Jira Task

[mikewilli]

Looks like this is related to Apple CPUs (per Legacy section at bottom of the project README):

Do you want Polars to run on an old CPU (e.g. dating from before 2011), or on an x86-64 build of Python on Apple Silicon under Rosetta? Install pip install polars-lts-cpu. This version of Polars is compiled without AVX target features.

Seems like we could just add this to the jetstream README. Also if there's an exception to catch, we could add a helpful log line to anyone running into this issue.