Fix GeoDataset for non-extension type column (e.g., overature)

[paleolimbot]

...works with overature! (Although sort of useless since its row groups are not spatially ordered)

import geoarrow.pyarrow as ga
uri = "s3://overturemaps-us-west-2/release/2023-07-26-alpha.0/theme=admins"
ds = ga.dataset(uri, geometry_columns=["geometry"])
ds.index_fragments()

[codecov]

Codecov Report

Merging #44 (1f8f952) into main (91d2ab9) will increase coverage by 1.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #44      +/-   ##
==========================================
+ Coverage   92.44%   93.45%   +1.01%     
==========================================
  Files          25       12      -13     
  Lines        4222     1498    -2724     
  Branches       59        0      -59     
==========================================
- Hits         3903     1400    -2503     
+ Misses        286       98     -188     
+ Partials       33        0      -33     

Files Changed	Coverage Δ
python/geoarrow/pyarrow/_dataset.py	99.52% <100.00%> (ø)

... and 13 files with indirect coverage changes