Update src/Client.js

Co-authored-by: Rajeh Taher <rajeh@reforward.dev>

Author: khsoh

src/Client.js

@@ -534,8 +534,8 @@ 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);
 
-                let newId = isParticipant ? msg.recipients[0] : msg._data.templateParams[1];
-                let oldId = isParticipant ? msg.author : msg._data.templateParams[0];
+                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.