UI: Use NVIDIA laptop GPU hint

Changes the default "preferred" GPU to the NVIDIA GPU when running the
program on NVIDIA laptops.

UI/obs-app.cpp

@@ -78,8 +78,9 @@ string opt_starting_collection;
 string opt_starting_profile;
 string opt_starting_scene;
 
-// AMD PowerXpress High Performance Flags
+// GPU hint exports for AMD/NVIDIA laptops
 #ifdef _MSC_VER
+extern "C" __declspec(dllexport) DWORD NvOptimusEnablement = 1;
 extern "C" __declspec(dllexport) int AmdPowerXpressRequestHighPerformance = 1;
 #endif