message: fix: show muc subject notification only on change
diff: @@ -33,11 +33,18 @@ export default class extends AbstractHandler {
  }
  if (subjectElement.length === 1 && bodyElement.length === 0) {
  - contact.setSubject(subjectElement.text());
  + let subject = subjectElement.text();
  + let oldSubject = contact.getSubject();
  +
  + if (subject === oldSubject) {
  + return this.PRESERVE_HANDLER;
  + }
  +
  + contact.setSubject(subject);
  let translatedMessage = Translation.t('changed_subject_to', {
  nickname,
  - subject: contact.getSubject()
  + subject,
  });
  contact.addSystemMessage(':page_with_curl: ' + translatedMessage);
  