Slider no longer "jumps" between defined steps, but makes smooth transitions with iOS 26.

## Environment

* Slider v5.x with the new architecture.
* iOS 26 used for the repro.

## Description

With the iOS 26 the behavior of native Slider changed. Beside having the liquid glass applied the slide movement is now smooth between defined steps, while it should be consistent with what was before v26 - Slider should make visible "jumps" between defined steps.

## Reproducible Demo

Any Slider instance with `step` defined will do to repro.

Start with a Slider v5.x instance using the new architecture and a defined step, then reproduce the behavior on iOS 26. Compare the smooth movement with the pre-iOS 26 behavior described in the issue. Done means defined steps produce visible jumps again on iOS while the existing Slider behavior remains intact.

索引モデルが issue の本文から書いたものです。