VideoCommon: Deinit Graphics Mod Manager implicitly

Source/Core/VideoCommon/VideoBackendBase.cpp

@@ -407,6 +407,7 @@ void VideoBackendBase::ShutdownShared()
 
   g_bounding_box.reset();
   g_perf_query.reset();
+  g_graphics_mod_manager.reset();
   g_texture_cache.reset();
   g_framebuffer_manager.reset();
   g_shader_cache.reset();