S3 serialization fix, delta func

[esoteric-ephemera]

• Ensure documents retrieved from S3 get serialized if use_document_model=True
• Move delta table stuff into separate function for organization
• No more xpass for blessed tasks, these are now live

[codecov-commenter]

Codecov Report

❌ Patch coverage is 9.37500% with 58 lines in your changes missing coverage. Please review.
✅ Project coverage is 71.84%. Comparing base (c0f976d) to head (eeba1a3).

Files with missing lines	Patch %	Lines
mp_api/client/core/client.py	9.37%	58 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1063      +/-   ##
==========================================
+ Coverage   71.80%   71.84%   +0.03%     
==========================================
  Files          55       55              
  Lines        3075     3079       +4     
==========================================
+ Hits         2208     2212       +4     
  Misses        867      867              

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