fix(python): Refactor is_between

[zundertj]

• no special datetime handling, is not needed, the underlying operators handle that properly
• added date and float to the type annotation. Closes pl.col(...).is_between is missing typing for date #5489
• add tests on the four data types allowed as input types

[thomasaarholt]

Nice! I think you can omit the int in the type hinting though, apparently float is enough.

https://stackoverflow.com/questions/50928592/mypy-type-hint-unionfloat-int-is-there-a-number-type/50928627#50928627

[zundertj]

@thomasaarholt : forgot about that, although I guess it is a trade-off in being a purist (dropping the int annotation), and making Polars users aware what types could be passed in as I expect that, like me, not everyone has it front of mind that float also implies int. That is also visible in the Polars code base: int | float occurs 61 times, float | int occurs 11 times.

[thomasaarholt]

Good point, and agreed :)