Function remove_from_chat_contacts_table_without_trace 

pub(crate) async fn remove_from_chat_contacts_table_without_trace(
    context: &Context,
    chat_id: ChatId,
    contact_id: ContactId,
) -> Result<bool>

Removes a contact from the chat without leaving a trace in the db. Returns whether the contact was removed, even if it was a past contact. If so, a removal message should be sent if the removal is issued by this device.

Note that if we call this function, and then receive a message from another device that doesn’t know that this this member was removed then the group membership algorithm will wrongly re-add this member.