Fix remaining issues with spectra Sdss.query_crossid

[bsipocz]

This PR fixes the failing test added in #2258 and fixes the code itself. Changelog is included for both PRs here.

[codecov]

Codecov Report

Merging #2304 (88c99be) into main (f99e1ba) will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##             main    #2304   +/-   ##
=======================================
  Coverage   62.84%   62.84%           
=======================================
  Files         130      130           
  Lines       16841    16841           
=======================================
  Hits        10584    10584           
  Misses       6257     6257           

Impacted Files	Coverage Δ
astroquery/sdss/core.py	85.76% <0.00%> (ø)

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