[python] One more rename in prep for domainish pushdown

[johnkerl]

Issue and/or context: As tracked on issue #2407 / [sc-51048].

Note that the intended Python and R API changes are all agreed on and finalized as described in #2407.

Changes:

Leveraging PRs on #2407 the full domain will be gotten from C++ libtiledbsoma with a simple cast in the pybind11/Rcpp layers.

However I missed one naming spot in the pybind11 layer.

Notes for Reviewer:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.79%. Comparing base (fa1fcc6) to head (219e1c2).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3026      +/-   ##
==========================================
+ Coverage   89.64%   89.79%   +0.14%     
==========================================
  Files          40       40              
  Lines        4096     4096              
==========================================
+ Hits         3672     3678       +6     
+ Misses        424      418       -6     

Flag	Coverage Δ
python	89.79% <100.00%> (+0.14%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
python_api	89.79% <100.00%> (+0.14%)	⬆️
libtiledbsoma	∅ <ø> (∅)

[johnkerl]

Thanks @nguyenv ! :)