Function emit_deleted_messages 

pub fn emit_deleted_messages(
    writer: &impl EventWriter<InternalEvent>,
    messages: Vec<StoredGroupMessage>,
    cause: DeletionCause,
    deleted_by_inbox_id: Option<String>,
    db: &impl DbQuery,
) -> Result<(), ConnectionError>

Emit the deletion of messages by the inbox deleted_by_inbox_id, or by no inbox (None) for a local removal of the rows.