Fix invalid hash for messages with a user

Only generating the hash for a message in the `ChatMessage` constructor
doesn't consider the fact that a message's user is often set in a child
class' contructor. A message's hash is derived from the user's ID, so
its hash also needs to be regenerated in this circumstance.

assets/chat/js/messages/ChatBroadcastMessage.js

@@ -7,6 +7,8 @@ export default class ChatBroadcastMessage extends ChatEventMessage {
     super(message, timestamp);
     this.type = MessageTypes.BROADCAST;
     this.user = user;
+
+    this.generateMessageHash();
   }
 
   buildUserTemplate(chat = null) {

assets/chat/js/messages/ChatDonationMessage.js

@@ -21,6 +21,8 @@ export default class ChatDonationMessage extends ChatEventMessage {
     this.type = MessageTypes.DONATION;
     this.amount = amount;
     this.expirationTimestamp = expirationTimestamp;
+
+    this.generateMessageHash();
   }
 
   html(chat = null) {

assets/chat/js/messages/ChatUserMessage.js

@@ -28,6 +28,8 @@ export default class ChatUserMessage extends ChatMessage {
     this.title = '';
     this.slashme = false;
     this.mentioned = [];
+
+    this.generateMessageHash();
   }
 
   html(chat = null) {