Fix handling of join messages of kind change.

static/galene.js

@@ -1470,6 +1470,11 @@ async function gotJoined(kind, group, perms, message) {
         this.close();
         return;
     case 'join':
+    case 'change':
+        displayUsername();
+        setButtonsVisibility();
+        if(kind === 'change')
+            return;
         break;
     default:
         displayError('Unknown join message');
@@ -1477,9 +1482,6 @@ async function gotJoined(kind, group, perms, message) {
         return;
     }
 
-    displayUsername();
-    setButtonsVisibility();
-
     let input = /** @type{HTMLTextAreaElement} */
         (document.getElementById('input'));
     input.placeholder = 'Type /help for help';