config(qt): Use qt_config directly to read config

ReadSetting with the default is a convenience function reading
settings,  not for use in an internal environment. It tries to manage
the default value of a setting.

src/yuzu/configuration/config.cpp

@@ -1271,9 +1271,11 @@ void Config::ReadSettingGeneric(Settings::BasicSetting* const setting) {
     }
 
     if (global || !use_global) {
-        const bool is_default = ReadSetting(name + QStringLiteral("/default"), true).value<bool>();
+        const bool is_default =
+            qt_config->value(name + QStringLiteral("/default"), true).value<bool>();
         if (!is_default) {
-            setting->LoadString(ReadSetting(name, default_value).value<QString>().toStdString());
+            setting->LoadString(
+                qt_config->value(name, default_value).value<QString>().toStdString());
         } else {
             // Empty string resets the Setting to default
             setting->LoadString("");