[python] Fix last 2.27+Python+dense failing test case

[johnkerl]

Issue and/or context: As tracked on issue #2407 / [sc-51048]. See also #3364.

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

Changes:

Following on #3263 and #3268 which deal with issues with core 2.27 and dense arrays. See also TileDB-Inc/centralized-tiledb-nightlies#25.

There is more work to be done for R tests at 2.27 (#3270) but this resolves the final issue with the Python side.

There is a TODO marked in the code on this PR: there are other cases which would have failed even at 2.26 and below, had they been written. This is addressed on #3271.

Notes for Reviewer:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.92%. Comparing base (945804c) to head (c69d037).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3269      +/-   ##
==========================================
+ Coverage   83.81%   83.92%   +0.11%     
==========================================
  Files          51       51              
  Lines        5578     5580       +2     
==========================================
+ Hits         4675     4683       +8     
+ Misses        903      897       -6     

Flag	Coverage Δ
python	83.92% <100.00%> (+0.11%)	⬆️

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

Components	Coverage Δ
python_api	83.92% <100.00%> (+0.11%)	⬆️
libtiledbsoma	∅ <ø> (∅)

[johnkerl]

Thanks @nguyenv !!