Fix FFZ emote assertion crash (#2192)

* Fix crash on null urls from FFZ API

* Update CHANGELOG.md

* Turns out there's an actual method for this

src/providers/ffz/FfzEmotes.cpp

@@ -14,7 +14,7 @@ namespace {
     Url getEmoteLink(const QJsonObject &urls, const QString &emoteScale)
     {
         auto emote = urls.value(emoteScale);
-        if (emote.isUndefined())
+        if (emote.isUndefined() || emote.isNull())
         {
             return {""};
         }