Column `matches` is broken for `dy.Enum`

[MoritzPotthoffQC]

Currently, matches fails when comparing Enum columns, apparently because polars identifies the column as a Series.

Minimum example:

import polars as pl
import dataframely as dy
column = dy.Enum(["foo"])
column.matches(column, pl.col("bar"))

Results in

TypeError: the truth value of a Series is ambiguous
                                                                                                                                 
Here are some things you might want to try:                                                                                      
- instead of `if s`, use `if not s.is_empty()`                                                                                   
- instead of `s1 and s2`, use `s1 & s2`                                                                                          
- instead of `s1 or s2`, use `s1 | s2`                                                                                           
- instead of `s in [y, z]`, use `s.is_in([y, z])`  

Afaict, this worked before #138, so maybe we need to look into that.

[AndreasAlbertQC]

Looks like we need another branch here that deals with pl.Series + a test that calls matches on Enum columns, which apparently is not happening yet