test(DataStore): Update schemas for use 'sub' as default identity claim feature

[div5yesh]

Issue #, if available:

Description of changes: The change in CLI tagged release @aws-amplify/[email protected] will provision backends and codegen the default identity claim as sub, previously cognito:username.

This PR is running automated tests related to the usage of @auth with default owner field in the schema.

The code generated model files contains the explicit identityClaim key, which has been updated from cognito:username to sub (see model schema file changes in this PR).

• [ ] Tests that were in place with regards to these schemas were tested.

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