[Vandita2020]

Issue #, if available

Description of changes

When SchemaRegistryConfig.SchemaRegistryURI is a Ref to a template parameter that has a value
(passed in or from Default), the intrinsics resolver returns a plain string. The code in
PullEventSource.get_schema_registry_permissions then called .get("Fn::Sub") on that string and
the transform failed with AttributeError: 'str' object has no attribute 'get'.

The resolved value is now handled as either a string or a dict:

• string: used as the registry ARN, so Glue permissions are generated for Glue registry ARNs
• dict (e.g. Fn::Sub): same behavior as before

Applies to both MSK and SelfManagedKafka events.

Description of how you validated changes

• Unit tests in test_msk_event_source.py and test_self_managed_kafka_event_source.py for
  SchemaRegistryURI as Ref to a Glue ARN parameter, Ref to a non-Glue URL parameter,
  Ref to an unresolved parameter, Ref to a resource, Fn::GetAtt and Fn::Sub.
• New transform test function_with_kafka_schema_registry_uri_ref_to_parameter (aws, aws-cn,
  aws-us-gov).
• The new tests that exercise the bug fail without the pull.py change and pass with it.
• tests/model, tests/schema and tests/translator pass.

Checklist

• Add/update transform tests
  • Using correct values
  • Using wrong values
• Add/update integration tests

Examples?

N/A