Config: Port BluetoothPassthrough settings to new config system.

Source/Core/Core/ConfigLoaders/IsSettingSaveable.cpp

@@ -27,7 +27,8 @@ bool IsSettingSaveable(const Config::Location& config_location)
   {
     for (const std::string_view section :
          {"NetPlay", "General", "GBA", "Display", "Network", "Analytics", "AndroidOverlayButtons",
-          "DSP", "GameList", "FifoPlayer", "AutoUpdate", "Movie", "Input", "Debug"})
+          "DSP", "GameList", "FifoPlayer", "AutoUpdate", "Movie", "Input", "Debug",
+          "BluetoothPassthrough"})
     {
       if (config_location.section == section)
         return true;

Source/Core/Core/ConfigLoaders/NetPlayConfigLoader.cpp

@@ -93,6 +93,8 @@ public:
 
     layer->Set(Config::SESSION_USE_FMA, m_settings.m_UseFMA);
 
+    layer->Set(Config::MAIN_BLUETOOTH_PASSTHROUGH_ENABLED, false);
+
     if (m_settings.m_StrictSettingsSync)
     {
       layer->Set(Config::GFX_HACK_VERTEX_ROUDING, m_settings.m_VertexRounding);