feat(scroll): change scroll dt to_pixels

[nuts-rice]

Objective

Fixes #24610

Solution

-current scroll conversion ratio after to_lines() was yielding 1px per notch for mousewheel scroll delta. It was converting scroll dt to line values then applying them to scroll_pos.y- which could be pixels instead.
-So I changed to to_pixels(). This applied to scroll dt yields 100px per notch .

Testing

-cargo run --example scroll is visually snappier. I'd be happy to provide comparison demo gifs if y'all want.
-Could tweak notch speed via MouseScrollPixelsPerLine

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[kfc35]

This makes sense to me since scroll_pos is in logical pixels as you mentioned

I tested this using a mac trackpad and scrolling still seems fine.