Revert "render: GetRenderViewportSize shouldn't use scale, just logical presentation."

This reverts commit ef758d05c154b6c052918de9f20a83d14b2065cd.

Turns out the bug in #11076 was that we were dropping texture draws
incorrectly, not that scale shouldn't be applied here. The dropped draw calls
were fixed in bf853209470c59f39101da91bb23099be6d286a1, and this revert is
making the renderer consistent again.

src/render/SDL_render.c

@@ -3000,8 +3000,8 @@ bool SDL_RenderViewportSet(SDL_Renderer *renderer)
 static void GetRenderViewportSize(SDL_Renderer *renderer, SDL_FRect *rect)
 {
     const SDL_RenderViewState *view = renderer->view;
-    const float scale_x = view->logical_scale.x;
-    const float scale_y = view->logical_scale.y;
+    const float scale_x = view->current_scale.x;
+    const float scale_y = view->current_scale.y;
 
     rect->x = 0.0f;
     rect->y = 0.0f;