ci(python): expand driver compatibility coverage

[youngsofun]

Summary

• expand the Python old-driver compatibility matrix with representative versions and dynamically resolve the latest PyPI release
• resolve the latest non-draft Databend nightly release for compatibility tests instead of relying on the moving nightly image tag
• default RUST_LOG to warn and enable Rust backtraces in all Python binding test variants while preserving caller-provided values
• skip load-file method tests and the microsecond interval assertion when the old driver API or behavior does not support them
• document version-gating requirements and keep the latest driver release in the compatibility matrix

Motivation

Databend runs newer binding tests against older driver versions to detect compatibility regressions. Keeping equivalent coverage in BendSQL catches unsupported test assumptions earlier and avoids blocking Databend development when a new test relies on behavior unavailable in an older driver or server.

Testing

• ruff format bindings/python/tests/asyncio/steps/binding.py bindings/python/tests/blocking/steps/binding.py bindings/python/tests/cursor/steps/binding.py tests/nox/noxfile.py
• nox -f tests/nox/noxfile.py --list
• CI=1 DATABEND_META_VERSION=v1.2.931-nightly DATABEND_QUERY_VERSION=v1.2.931-nightly nox -R -f tests/nox/noxfile.py -s "new_test_with_old_drivers(driver_version='0.34.2', query_result_format='arrow')"
• CI=1 DATABEND_META_VERSION=v1.2.931-nightly DATABEND_QUERY_VERSION=v1.2.931-nightly nox -R -f tests/nox/noxfile.py -s "new_test_with_old_drivers(driver_version='0.34.2', query_result_format='json')"
• CI=1 DATABEND_META_VERSION=v1.2.931-nightly DATABEND_QUERY_VERSION=v1.2.931-nightly nox -R -f tests/nox/noxfile.py -s "new_test_with_old_drivers(driver_version='0.27.6', query_result_format='json')"
• CI=1 DATABEND_META_VERSION=v1.2.931-nightly DATABEND_QUERY_VERSION=v1.2.931-nightly nox -R -f tests/nox/noxfile.py -s "new_test_with_old_drivers(driver_version='latest', query_result_format='json')"
• ruby -e 'require "yaml"; YAML.load_file(".github/workflows/bindings.python.yml")'
• git diff --check