DM-38689: Update _standardize_muli_index_columns to be faster for dataframe del…

[erykoff]

…egates.

Checklist

• ran Jenkins
• added a release note for user-visible changes to doc/changes

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.01 ⚠️

Comparison is base (220d528) 87.75% compared to head (47f18df) 87.74%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #823      +/-   ##
==========================================
- Coverage   87.75%   87.74%   -0.01%     
==========================================
  Files         268      268              
  Lines       34932    34929       -3     
  Branches     7347     7347              
==========================================
- Hits        30653    30650       -3     
  Misses       3125     3125              
  Partials     1154     1154              

Impacted Files	Coverage Δ
python/lsst/daf/butler/delegates/dataframe.py	95.55% <ø> (-0.19%)	⬇️
python/lsst/daf/butler/formatters/parquet.py	93.71% <100.00%> (-0.02%)	⬇️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.

[timj]

I don't really follow all of it but it does indeed seem better to use the columns you already knew about.

[erykoff]

All of this code is about dealing with the way you can specify multi-index columns of dataframes as tuples, and how this looks slightly different for arrow tables and dataframes. But I didn't write the original code.
This update here is just making the utility function use a MultiIndex which saves unnecessary overhead when using it in the delegate where we have an explicit dataframe.