Clarify the CNAME set up process in case of client owned certificates

Hey team.
About CNAME set up in case the client need to use their own certificates.
The article reports as follow:

> "If you currently manage your own certificates, you are responsible for purchasing, maintaining, and providing a certificate to Adobe for first-party cookie use. You can contact Adobe Customer Care to discuss migrating to the Adobe-managed certificate program."

It is mentioned to contact the Customer Care, but it's not clear if that holds for the owned certificates as well.
Could you please adjust the article and make it more explicit:

- Does Adobe-managed certificate service support client's owned certificates?
- In case of client owned certificate, should a customer care ticket be opened?

Thanks!!

Issue in ./help/interface/data-collection/adobe-managed-cert.md

Start with ./help/interface/data-collection/adobe-managed-cert.md and review the existing CNAME and certificate wording. Confirm from the project’s guidance whether Adobe-managed certificates support client-owned certificates and whether a Customer Care ticket is required. Done means the article explicitly answers both questions.

Written by the indexing model from the issue text.