[python] Performance improvement for experiment-level resize

[johnkerl]

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

Changes:

Make this more performant in the most common case. This helps with larger datasets stored remotely, as found by experiment.

Notes for Reviewer:

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 85.49%. Comparing base (208c0ab) to head (c50bc34).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3308      +/-   ##
==========================================
+ Coverage   85.37%   85.49%   +0.11%     
==========================================
  Files          52       52              
  Lines        5499     5508       +9     
==========================================
+ Hits         4695     4709      +14     
+ Misses        804      799       -5     

Flag	Coverage Δ
python	85.49% <75.00%> (+0.11%)	⬆️

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Components	Coverage Δ
python_api	85.49% <75.00%> (+0.11%)	⬆️
libtiledbsoma	∅ <ø> (∅)