[Logging]Disable logging unless users explicitly set the samplePercent

[yuli-han]

Summary

Previously, all Joins had logging enabled by default at 100% sample rate. From statistics for Airbnb users, nearly 96% of the new joins has sample percent 100%. This caused unnecessary logging overhead for users who didn't need it.

Disable request logging by default for Joins unless users explicitly set sample_percent.

Changes

• Changed sample_percent default from 100.0 to None in the Python Join API
• Updated test fixtures to explicitly set sample_percent=100.0 where logging is expected
• Updated docstring to document the new default behavior

Usage

Before: logging enabled by default
Join(left=..., right_parts=...)

After: logging disabled by default, must explicitly enable
Join(left=..., right_parts=..., sample_percent=100.0)

Why / Goal

Test Plan

• Added Unit Tests
• Covered by existing CI
• Integration tested

Checklist

• Documentation update

Reviewers

@pengyu-hou @hzding621 @Shiyinghaha

[pengyu-hou]

Thanks for the quick change.