Fixed contact_changed event to get the correct newId and oldId

Author: khsoh

src/Client.js

@@ -700,10 +700,8 @@ class Client extends EventEmitter {
                     /** @type {GroupNotification} object does not provide enough information about this event, so a @type {Message} object is used. */
                     const message = new Message(this, msg);
 
-                    const newId = isParticipant ? msg.recipients[0] : msg.to;
-                    const oldId = isParticipant
-                        ? msg.author
-                        : msg.templateParams.find((id) => id !== newId);
+                    const newId = isParticipant ? msg.recipients[0] : msg._data.templateParams[1];
+                    const oldId = isParticipant ? msg.author : msg._data.templateParams[0];
 
                     /**
                      * Emitted when a contact or a group participant changes their phone number.