Replace QDir("libraries/").absolutePath() with metacache solution

Signed-off-by: TheKodeToad <TheKodeToad@proton.me>

launcher/minecraft/MinecraftInstance.cpp

@@ -1036,7 +1036,7 @@ QMap<QString, QString> MinecraftInstance::makeProfileVarMapping(std::shared_ptr<
     result["assets_root"] = absAssetsDir;
     result["assets_index_name"] = assets->id;
 
-    result["library_directory"] = QDir("libraries/").absolutePath();
+    result["library_directory"] = APPLICATION->metacache()->getBasePath("libraries");
 
     return result;
 }