Review Request #2503 — Created July 7, 2023 and submitted
I realized I needed this when I started porting XMPP to the new Contact API. I need to be able to get a list of all the groups that a contact is in so I can updated them appropriately but we didn't have the api for it. This is something that other protocols will need to do as well so here's the API.
Ran the unit tests.