Fixed ray session fixture for uv run

[jx2lee]

Summary

Closes #3318. (cc. @Fokko)

• use a temporary working directory for the session-scoped Ray fixture
• disable Ray's uv runtime-env hook before importing Ray in ray_session

Testing

• uv run pytest tests/integration/test_reads.py -m integration -k 'test_ray_' -vv

before upgrading

❯ uv run pytest tests/integration/test_reads.py -m integration -k 'test_ray_'; uv pip list | grep ray
===================================================================== test session starts ======================================================================
platform darwin -- Python 3.10.19, pytest-9.0.3, pluggy-1.6.0
rootdir: /Users/jj/workspace/opensource/iceberg-python
configfile: pyproject.toml
plugins: mock-3.15.1, anyio-4.11.0, lazy-fixtures-1.4.0, checkdocs-2.14.0, requests-mock-1.12.1
collected 109 items / 101 deselected / 8 selected

tests/integration/test_reads.py ....ss..                                                                                                                 [100%]

======================================================== 6 passed, 2 skipped, 101 deselected in 15.67s =========================================================
aws-xray-sdk                  2.15.0
ray                           2.54.1

after,

❯ uv run pytest tests/integration/test_reads.py -m integration -k 'test_ray_'; uv pip list | grep ray
===================================================================== test session starts ======================================================================
platform darwin -- Python 3.10.19, pytest-9.0.3, pluggy-1.6.0
rootdir: /Users/jj/workspace/opensource/iceberg-python
configfile: pyproject.toml
plugins: mock-3.15.1, anyio-4.11.0, lazy-fixtures-1.4.0, checkdocs-2.14.0, requests-mock-1.12.1
collected 109 items / 101 deselected / 8 selected

tests/integration/test_reads.py ....ss..                                                                                                                 [100%]

======================================================== 6 passed, 2 skipped, 101 deselected in 15.01s =========================================================
aws-xray-sdk                  2.15.0
ray                           2.55.1

[kevinjqliu]

Thanks @jx2lee this issue is fixed in https://github.com/apache/iceberg-python/pull/3299/files#diff-e52e4ddd58b7ef887ab03c04116e676f6280b824ab7469d5d3080e5cba4f2128R3032-R3038