✅ Add test that runs select with 3 or 4 arguments

[svlandeg]

Ensure that _expression_select_gen.py works properly and provides the right type hints for code that calls select() with 3 or 4 arguments.

Note that I already provided some code to call select with 5 arguments as well. This works and runs, but won't succeed on a mypy check, as reported before.

While I think this PR is useful on its own, it's also in preparation of #1560.

[tiangolo]

Nice, let's get this in, thank you! 🚀