fix(DataStore): Fixing a crash when attempting to create a model with a predicate

[ruisebas]

Issue #

• Crash when saving data using datastore #3595

Description

Setting a predicate on a save operation with a model that does not exist is not supported. The StorageEngine performs this validation and reports a failure to the completion handler if attempted. However, the execution is not interrupted and then StorageAdapter is still invoked, which also fails and also reports a failure.

This results in the plugin's continuation being resumed twice, which results in a crash with SWIFT TASK CONTINUATION MISUSE.

The fix is simple, we're just missing a return statement in the initial validation after we invoke the completion callback.

General Checklist

• Added new tests to cover change, if needed
• Build succeeds with all target using Swift Package Manager
• All unit tests pass
• All integration tests pass
  • DataStore: https://github.com/aws-amplify/amplify-swift/actions/runs/8602460009
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Documentation update for the change if required
• PR title conforms to conventional commit style
• New or updated tests include Given When Then inline code documentation and are named accordingly testThing_condition_expectation()
• If breaking change, documentation/changelog update with migration instructions

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