Photo search: Set window title on Windows (#987)

Updates the window title to "Desktop Photo Search" in the Windows
build of desktop_photo_search.

experimental/desktop_photo_search/windows/runner/main.cpp

@@ -27,7 +27,7 @@ int APIENTRY wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev,
   FlutterWindow window(project);
   Win32Window::Point origin(10, 10);
   Win32Window::Size size(1280, 720);
-  if (!window.CreateAndShow(L"desktop_photo_search", origin, size)) {
+  if (!window.CreateAndShow(L"Desktop Photo Search", origin, size)) {
     return EXIT_FAILURE;
   }
   window.SetQuitOnClose(true);