Type Alias: ContactId
ContactId:
Brand<`${AccountNumber}@${ChatServer}`,"ContactId">
A contact id ends with @c.us and only contains the number of the contact. For example, if the country code of a contact is 44 and their number is 7123456789 then the contact id would be 447123456789@c.us
Example:
"447123456789@c.us"