fix: controller cursor speed no longer scales with framerate

When framerate was uncapped (vsync off, high-end hardware), the controller cursor in the inventory and creative menus moved way too fast. Basically unusable unless you switched to the dpad. The cursor update was tied to how often the screen redraws, so the faster the game ran, the faster the cursor flew.

Now the cursor moves a smaller distance per frame at higher framerates, so the actual on-screen speed stays the same whether you're at 60 FPS or 600 FPS.

While fixing this I also found an old workaround that was rounding the cursor position to whole pixels every frame and nudging it by 1 pixel to keep it from getting stuck. That nudge was pointing the wrong way on the vertical axis, which made up/down movement feel broken once the per-frame distance got small. Removed the rounding and the nudge. The cursor can now hold a fractional position between frames, and the part of the code that actually draws the cursor still snaps it to whole pixels on screen.

Fixes #3

Minecraft.Client/Common/UI/IUIScene_AbstractContainerMenu.h

@@ -145,6 +145,8 @@ protected:
 
 	int		m_iConsectiveInputTicks;
 
+	int64_t	m_iLastMouseTickTimeNs;
+
 	// Used for detecting quick "taps" in a direction, should jump cursor to next slot.
 	enum ETapState
 	{