jplhorizons remove deprecated columns in the code

There are a few deprecated columns that are no longer being queried, but remaining in the ``__init__.py``:

https://github.com/astropy/astroquery/blob/9387c450137dd6ed0f9c2c96df4abfcf201059a8/astroquery/jplhorizons/__init__.py#L104-L113

I think it is safe to remove those lines because the HORIZONS no longer returns such columns...?

Start in astroquery/jplhorizons/__init__.py at the linked lines 104–113 and verify which columns are deprecated and no longer returned by HORIZONS. Remove only the obsolete column definitions, then run the relevant jplhorizons tests or checks to confirm current responses and behavior remain valid.

Written by the indexing model from the issue text.