[c++] Reduce deprecation-warning lines in CI build logs

[johnkerl]

Quick drive-by on #2939 for issue #2407 / [sc-51048].

Looking through CI build logs, it's preferable to not have to scroll past a few screenfuls of deprecation warnings.

Example:

• https://github.com/single-cell-data/TileDB-SOMA/actions/runs/10620570698/job/29440624989
• https://gist.github.com/johnkerl/24caca3f819241215363c4adae888a05 lines 1459-6522

See also #2581

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.02%. Comparing base (c8d6ca2) to head (9d83be6).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2941      +/-   ##
==========================================
+ Coverage   89.87%   90.02%   +0.15%     
==========================================
  Files          38       38              
  Lines        3999     3999              
==========================================
+ Hits         3594     3600       +6     
+ Misses        405      399       -6     

Flag	Coverage Δ
python	90.02% <ø> (+0.15%)	⬆️

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

Components	Coverage Δ
python_api	90.02% <ø> (+0.15%)	⬆️
libtiledbsoma	∅ <ø> (∅)