test(datastore): Refactor test names/comment and add OCC fake

[stocaaro]

Description of changes

Warning

PR reconstructed against main - Please see aws-amplify#12740

Outcome:

• Test names changed to align with the harness features used per test
• Add clear harness feature comments for each first use of a feature
• Add the core logic for simulating OptimisticConcurrency service calls to the service Fake
• Move harness.outboxSettled calls into harness behavior where they aren't adding inline clarity

The diff associated with this change is really hard to parse. If you hide whitespace it is much clearer what is happening.

Description of how you validated changes

Tests continue to pass with the same asserted outcomes.

Related changes

1. refactor(datastore): Move conflict resolution tests to their own file aws-amplify/amplify-js#12728
2. refactor(datastore): Refactor conflict resolution tests optimize for concise/readable aws-amplify/amplify-js#12732
3. 🌱 test(datastore): Refactor test names/comment and add OCC fake
4. refactor(datastore): Add OptimisticConcurrency tests #86
5. fix(datastore): Update outbox comparison logic to fix update versioning problems #87

Checklist

• PR description included
• yarn test passes

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.