Fix typo in code comment for clarity

[lkb85]

Summary

Fixed typos in code comments in the following files: api/py/test/test_group_by.py and api/py/ai/chronon/join.py.

Why / Goal

Improve code readability and maintainability by correcting typographical errors in comments.

Test Plan

• Covered by existing CI

Checklist

• N/A

Reviewers

N/A

[caiocamatta-stripe]

Thank you for your interest in the Chronon repo. I'm unsure what the real motivation to merge this auto-generated change is.

[pengyu-hou]

Thank you for your interest in the Chronon repo. I'm unsure what the real motivation to merge this auto-generated change is.

@caiocamatta-stripe Actually, this is not auto-generated, this seems a legit correction.