fix: don't convert dense matrices to COO in feature_is_filtered validation

[nayib-jose-gloria]

Reason for Change

• memory spikes on dense matrices in prod, don't need to convert those to COO to enable dask summation

Changes

• don't convert dense matrices to COO

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Please upload report for BASE (main@468f06f). Learn more about missing BASE report.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1398   +/-   ##
=======================================
  Coverage        ?   89.17%           
=======================================
  Files           ?       23           
  Lines           ?     2587           
  Branches        ?        0           
=======================================
  Hits            ?     2307           
  Misses          ?      280           
  Partials        ?        0           

Components	Coverage Δ
cellxgene_schema_cli	89.72% <100.00%> (?)
migration_assistant	91.26% <ø> (?)
schema_bump_dry_run_genes	79.74% <ø> (?)
schema_bump_dry_run_ontologies	99.51% <ø> (?)

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