LibWeb/Gamepad: Forward declare SDL components to fix Windows build

We have to prevent from including any SDL headers in LibWeb headers.
Otherwise there will be transitive Windows.h includes that will
re-declare some of our existing forward decls/defines in
LibCore/SocketAddressWindows.h

Libraries/LibWeb/Gamepad/Gamepad.cpp

@@ -16,6 +16,8 @@
 #include <LibWeb/HTML/Window.h>
 #include <LibWeb/HighResolutionTime/TimeOrigin.h>
 
+#include <SDL3/SDL_gamepad.h>
+
 namespace Web::Gamepad {
 
 GC_DEFINE_ALLOCATOR(Gamepad);