added test case for ssm_patch_manager_enabled

[Khushi-Kalantri-Comprinno]

Context

Adding unit test coverage for the ssm_patch_manager_enabled check to validate that AWS Systems Manager Patch Manager is enabled on SSM-managed EC2 instances.

Description

• Created test_ssm_patch_manager_enabled.py with multiple test cases:
  • No running EC2 instances
  • Instance not managed by SSM
  • Instance managed by SSM but Patch Manager not enabled
  • Instance managed by SSM and Patch Manager enabled
  • Error handling for describe_instance_information failure
• Ensured test discovery by adding a dummy test.
• Mocked EC2 and SSM clients to isolate unit tests.

Checklist

• Added new checks? If yes, reviewed necessary permissions
• Code covered by tests (if not, explain why)
• Documentation follows Google Python Style Guide
• Considered if backporting is needed

License

I confirm that my contribution is made under the terms of the Apache 2.0 license.