Preserve points feature_key in queries

[quentinblampey]

In bounding_box/polygon queries, the "feature_key" of points was not preserved.

• preserve feature_key in bounding_box
• preserve feature_key in polygon
• tests added

While fixing that, I also found (and fixed) a minor issue in the PointsModel.parse method when passing feature_key. Indeed, if corresponding column is already a category, it is dropped from the dataframe, see the line below:

if feature_key is not None and data[feature_key].dtype.name != "category":
    table[feature_key] = data[feature_key].astype(str).astype("category")

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.80%. Comparing base (94f0a31) to head (d2be524).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #794   +/-   ##
=======================================
  Coverage   91.80%   91.80%           
=======================================
  Files          45       45           
  Lines        6954     6959    +5     
=======================================
+ Hits         6384     6389    +5     
  Misses        570      570           

Files with missing lines	Coverage Δ
src/spatialdata/_core/query/spatial_query.py	95.50% <100.00%> (+0.03%)	⬆️
src/spatialdata/models/_utils.py	90.41% <ø> (ø)
src/spatialdata/models/models.py	87.84% <100.00%> (+0.05%)	⬆️

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[LucaMarconato]

Looks great to me thanks! Fixing the docs and then merging.