getContactFromId
Retrieves a contact based on their identifier.
This method searches for a contact with the specified ID. The contact can be retrieved from the cache if it's present in the user's roster, designated as a personal contact, or fetched from the server using the fetchContactDataById method.
Return
The IRainbowContact object corresponding to the specified ID, or null if the contact is not found.
Parameters
contactId
The identifier of the contact to retrieve.