Upgrade state manager component

[CaptainOfHacks]

• update documentation for state manager
• enable unit tests for state manager
• update logic of state manager component
• update mongomock with GridFS support version

[swarmia]

✅  Linked to Task MWB-271 · Update MongoMock and enable GridFS unit tests, update StateManager

[codecov]

Codecov Report

Attention: 18 lines in your changes are missing coverage. Please review.

Comparison is base (be78013) 0.00% compared to head (a7ecfa8) 0.00%.
Report is 5 commits behind head on main.

Files	Patch %	Lines
...kbench/backend/database/adapters/gridfs_storage.py	0.00%	13 Missing ⚠️
...end/state_manager/services/object_state_manager.py	0.00%	5 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main     #46   +/-   ##
=====================================
  Coverage   0.00%   0.00%           
=====================================
  Files         94      94           
  Lines       2824    2833    +9     
=====================================
- Misses      2824    2833    +9     

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