chore(test): add integration test cases of CPK for API lazy loading

[5d]

Issue #

Description

• Add integration test cases for CPK(Composite Primary Key) LazyLoading cases of subscription API.

General Checklist

• [X] Added new tests to cover change, if needed
• [X] Build succeeds with all target using Swift Package Manager
• [X] All unit tests pass
• [X] All integration tests pass
• [ ] ~Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)~
• [X] Documentation update for the change if required
• [X] PR title conforms to conventional commit style
• [X] 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.