Thumb and steps are not aligned

## Environment
"react-native": "^0.78.0",
"react": "18.3.1",
"@react-native-community/slider": "^4.5.6"
"expo": "^52.0.37",

on expo web

## Description

Slider thumb and steps seem to not have the same padding

- I fixed it by translateX of the stepMarker to : ((element.index - element.min) / (element.max - element.min) - 0.5) * 34 but it's not ideal
- I prefer the way the steps are positioned. It might be the opportunity to look at the padding of the steps inside the slider and add it as a prop ?

在 Expo web 上使用报告的 React Native Slider 版本复现 slider，并比较 issue 图片中显示的 thumb 和 step-marker 位置。检查 step-marker 的定位和 padding 行为，然后确认 marker 无需报告中的 translateX workaround 即可与 thumb 对齐。

由索引模型根据 Issue 内容生成。