GH-3392 dirty initial MSA support that shares logic with Mojang flows

Both act as the first step of AuthContext.

launcher/minecraft/auth/AuthSession.cpp

@@ -7,11 +7,13 @@
 QString AuthSession::serializeUserProperties()
 {
     QJsonObject userAttrs;
+    /*
     for (auto key : u.properties.keys())
     {
         auto array = QJsonArray::fromStringList(u.properties.values(key));
         userAttrs.insert(key, array);
     }
+    */
     QJsonDocument value(userAttrs);
     return value.toJson(QJsonDocument::Compact);