add GetContactByID to Messenger

Signed-off-by: Jakub Sokołowski <jakub@status.im>

protocol/messenger.go

@@ -1147,10 +1147,20 @@ func (m *Messenger) Contacts() []*Contact {
 	for _, contact := range m.allContacts {
 		contacts = append(contacts, contact)
 	}
-
 	return contacts
 }
 
+// GetContactByID assumes pubKey includes 0x prefix
+func (m *Messenger) GetContactByID(pubKey string) (*Contact, error) {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+	contact, ok := m.allContacts[pubKey]
+	if !ok {
+		return nil, errors.New("no contact found")
+	}
+	return contact, nil
+}
+
 // ReSendChatMessage pulls a message from the database and sends it again
 func (m *Messenger) ReSendChatMessage(ctx context.Context, messageID string) error {
 	m.mutex.Lock()