Parsing to Decimal ignores decimal_comma when reading from csv

[matterhorn103]

Now that there is the option to pass decimal_comma=True to read_csv(), it would be great if this was heeded when a schema has specified to parse a column as pl.Decimal.

This would be particularly useful for financial data, as Decimal often is, where the values in euros (German bank) are in my dataset in the form 265,64.