SDL3: fix renderer logical presentation

[cheyao]

This pull request fixes some clipping issues and mouse offset issues (should it be called this?) with SDL's logical presentation when using sdlrenderer back-end with SDL3.

Here is a video of the behavior after the change and before the change: (Sorry for the bad video quality)
https://imgur.com/a/w9XrzaJ

You can test this change by going to examples/example_sdl3_sdlrenderer3 and adding this after initializing the renderer:

SDL_SetRenderLogicalPresentation(renderer, 1024, 768,
					SDL_LOGICAL_PRESENTATION_LETTERBOX,
					SDL_SCALEMODE_BEST);

and this right after polling the event

SDL_ConvertEventToRenderCoordinates(renderer, &event);