SDL3: Remove usage of SDL_DelayNS in sleep calls.

SDL3 currently busy-waits in its implementation, which defeats the purpose of the sleep calls.

src/common/delay.cpp

@@ -31,16 +31,12 @@
 namespace love
 {
 
-// TODO: use ns.
+// TODO: use ns. https://github.com/libsdl-org/SDL/issues/11141
 void sleep(double ms)
 {
 	// We don't need to initialize the SDL timer subsystem for SDL_Delay to
 	// function - and doing so causes SDL to create a worker thread.
-#if SDL_VERSION_ATLEAST(3, 0, 0)
-	SDL_DelayNS(SDL_MS_TO_NS(ms));
-#else
 	SDL_Delay((Uint32)ms);
-#endif
 }
 
 } // love