[python] Support pypaimon-rust 0.4

[shyjsarah]

Purpose

pypaimon[sql] currently caps pypaimon-rust below 0.4.0. After paimon-rust bumped its workspace version to 0.4.0, installing the source-built Python binding followed by pypaimon[sql] makes pip reject the installed binding and try to resolve an older wheel.

Changes

• Allow the SQL extra to use both pypaimon-rust 0.3.x and 0.4.x.
• Pin the Python 3.11 CI lane to the paimon-rust 0.4.0 version-bump commit.
• Install pypaimon[sql] in that lane so CI verifies the package metadata accepts the source-built binding.

Testing

• Built and installed pypaimon-rust 0.4.0 from source in a clean Python 3.10 virtual environment.
• Verified python -m pip install --dry-run './paimon-python[sql]' recognizes the installed pypaimon-rust 0.4.0.
• Parsed .github/workflows/paimon-python-checks.yml as YAML.
• Ran git diff --check.