Add support to Update a Custom Domain

[kailash-b]

Changes

Please describe both what is changing and why this is important. Include:

• PATCH /api/v2/custom-domains/{id}
• Added tls_policy and custom_client_ip_header fields in the models that were missing them.

References

Please include relevant links supporting this change such as a:

• SDK-5495

Testing

Tests for custom domains are limited. We cannot test full CRUD sequence because the tenants allow for only one custom domain and others depend on that domain.
We are therefore limited in scope to what we can test.
For now, we have updated the test that we run manually to verify that the basic serialization and the GET methods work properly.

• This change adds unit test coverage

• This change adds integration test coverage

• This change has been tested on the latest version of the platform/language or why not

Checklist

• I have read the Auth0 general contribution guidelines

• I have read the Auth0 Code of Conduct

• All existing and new tests complete without errors