Raise a helpful error message when the user is accessing a catalog's column that hasn't been loaded.

[gitosaurus]

Now that we have default columns for catalogs, there are usually columns available on disk that aren't pulled into memory, and this is even more true when the columns= argument is used. When the user tries to reference columns that are part of the catalog but which weren't loaded, the error messages imply that the columns were never available. Instead, building on the all_columns property, give a more specific error when the user tries to access an unloaded column.

Closes #685 and #765 .

[github-actions]

Before [fc62489]	After [7235a0d]	Ratio	Benchmark (Parameter)
6.51±0.03s	6.50±0.03s	1	benchmarks.time_create_large_catalog
28.7±0.6ms	28.8±0.5ms	1	benchmarks.time_polygon_search
978±8ms	969±10ms	0.99	benchmarks.time_create_midsize_catalog
86.0±1ms	85.4±2ms	0.99	benchmarks.time_kdtree_crossmatch
14.4±0.3ms	13.8±0.2ms	0.96	benchmarks.time_box_filter_on_partition

Click here to view all benchmarks.

[codecov]

Codecov Report

❌ Patch coverage is 98.03922% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 97.42%. Comparing base (fc62489) to head (7518af1).
⚠️ Report is 211 commits behind head on main.

Files with missing lines	Patch %	Lines
src/lsdb/catalog/catalog.py	94.44%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #766      +/-   ##
==========================================
+ Coverage   97.33%   97.42%   +0.09%     
==========================================
  Files          53       53              
  Lines        2325     2371      +46     
==========================================
+ Hits         2263     2310      +47     
+ Misses         62       61       -1     

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