Stop shipping unit tests in photonlibpy wheel

[auscompgeek]

Description

The photonlibpy wheels currently contain a test package with everything in //photon-lib/py/test. This is most certainly not intended to be shipped to users on sys.path.

This package was being picked up due to this:

photonvision/photon-lib/py/setup.py

Line 56 in 8a14190

packages=find_packages(),

There's no reason for this test subdirectory to be a Python package, so remove the __init__.py.

Meta

Merge checklist:

• Pull Request title is short, imperative summary of proposed changes
• The description documents the what and why
• If this PR changes behavior or adds a feature, user documentation is updated
• If this PR touches photon-serde, all messages have been regenerated and hashes have not changed unexpectedly
• If this PR touches configuration, this is backwards compatible with settings back to v2025.3.2
• If this PR touches pipeline settings or anything related to data exchange, the frontend typing is updated
• If this PR addresses a bug, a regression test for it is added