Fancy Effects 2021-2024 gone but never forgotten

Remove fancy effects as it's busted and causing CPU spikes.

(cherry picked from commit dc2f11eb2b)

src/models/messageeventmodel.h

@@ -140,5 +140,4 @@ private:
 
 Q_SIGNALS:
     void roomChanged();
-    void fancyEffectsReasonFound(const QString &fancyEffect);
 };