Add type and states to filter_subscribers()

[n7studios]

Summary

Adds support for type and states parameters for the filter_subscribers() method.

Testing

• testFilterSubscribersWithInvalidParameters: Test that a ClientException is thrown when invalid parameters are sent to the API.

Checklist

• I have written a test and included it in this PR
• I have run all tests and they pass
• The code passes when running the PHP CodeSniffer
• The code passes when running PHPStan
• I have assigned a reviewer or two to review this PR (if you're not sure who to assign, we can do this step for you)