chore(api): Add github workflow for Functional and GraphQLIAM tests

[lawmicha]

Issue #, if available:

Description of changes:
Similar to DataStore (#2115), added API integration testing into the github actions workflows

Check points: (check or cross out if not relevant)

• 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
• 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
• 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.

[lawmicha]

Disabling GraphQL IAM tests due to backend mismatch with the latest, not exactly sure what the mismatch is but we changed the readme schema slightly (added public/private IAM auth) and using V2 transformer. This PR now only adds Functional tests to the pipeline and are passing:

https://github.com/aws-amplify/amplify-ios/runs/7772776155?check_suite_focus=true