fix: fix possible composite key collision in StubDatabaseAdapter test utility

[wschurman]

Why

The stub adapters were doing a simple : join, so it was possible for two rows to collide in the stub adapter during tests, if value has the delimiter.

How

Fix is to use JSON.stringify so that only truly same rows map to the same thing.

Test Plan

Run new tests.

[wschurman]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
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• fix: correctness of TSMockitoExtensions isEqualWithEntityAware for SerializableKeyMaps of different length #614
• fix: fix possible composite key collision in StubDatabaseAdapter test utility #613 👈 (View in Graphite)
• chore: update comment for IEntityMetricsAdapter for implementors #612
• fix: pick method crash when object has hasOwnProperty key #611
• fix: fix behavior of AuthorizationResultBasedEntityAssociationLoader when field value is empty string #610
• feat: support numeric enums in StrictEnumField #609
• feat: validate GenericRedisCacheContext #608
• fix: skip when AllowIfAllSubRulesAllowPrivacyPolicyRule is empty #607
• fix: correct cycle guard behavior for deletion #606
• fix: handle potential infinite recursion for canViewerDeleteAsync #605
• feat: clean up transactional dataloader at transaction end #604
• fix: correct negative caching behavior in GenericSecondaryEntityCache #603
• fix: update cache key generation for secondary caches #602
• fix!: replace makeKeyFn with delimiter to strengthen guarantee of proper escaping #601
• fix: prevent collision in companion when entities share same name or same table name #600
• chore: remove unnecessary ViewerScopedEntityMutatorFactory #599
• main

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (925c810) to head (fb9f279).

Additional details and impacted files

@@                                           Coverage Diff                                           @@
##           05-14-chore_update_comment_for_ientitymetricsadapter_for_implementors      #613   +/-   ##
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  Coverage                                                                 100.00%   100.00%           
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  Files                                                                        109       109           
  Lines                                                                      17741     17741           
  Branches                                                                     917       932   +15     
=======================================================================================================
  Hits                                                                       17741     17741           

Flag	Coverage Δ
integration	28.62% <0.00%> (ø)
unittest	94.53% <100.00%> (ø)

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