Cannot sort by multiple columns including Decimal column

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Checks

• I have checked that this issue has not already been reported.
• I have confirmed this bug exists on the latest version of Polars.

Reproducible example

import polars as pl

df = pl.DataFrame({"a": [None], "b": [None]}, schema={"a": pl.Decimal(), "b": pl.Int64})
result = df.sort("a", "b")
print(result)

Log output

Traceback (most recent call last):
  File "/home/stijn/code/polars/py-polars/repro.py", line 8, in <module>
    result = df.sort("a", "b")
             ^^^^^^^^^^^^^^^^^
  File "/home/stijn/code/polars/py-polars/polars/dataframe/frame.py", line 4727, in sort
    .collect(_eager=True)
     ^^^^^^^^^^^^^^^^^^^^
  File "/home/stijn/code/polars/py-polars/polars/lazyframe/frame.py", line 1896, in collect
    return wrap_df(ldf.collect(callback))
                   ^^^^^^^^^^^^^^^^^^^^^
polars.exceptions.InvalidOperationError: `arg_sort_multiple` operation not supported for dtype `decimal[*,0]`

Issue description

This sort is not supported, when it should be.

Expected behavior

Sorting works.

Installed versions

main