LibWeb: Add tests for Gamepad API by utilising virtual SDL3 joysticks

Author: https://github.com/Lubrsi
Commit: 9adf27f009
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/5902
Reviewed-by: https://github.com/gmta
Reviewed-by: https://github.com/trflynn89

Libraries/LibWeb/Internals/Internals.idl

@@ -1,6 +1,7 @@
 #import <DOM/EventTarget.idl>
 #import <HTML/HTMLElement.idl>
 #import <Internals/InternalAnimationTimeline.idl>
+#import <Internals/InternalGamepad.idl>
 
 [Exposed=Nobody]
 interface Internals {
@@ -58,4 +59,8 @@ interface Internals {
     // Returns the shadow root of the element, if it has one, even if it's not normally accessible to JS.
     ShadowRoot? getShadowRoot(Element element);
 
+    undefined handleSDLInputEvents();
+
+    InternalGamepad connectVirtualGamepad();
+
 };