[Story interactive] Touch target size

### Description

Touch targets should be [at least 48 x 48 px](https://material.io/develop/web/supporting/touch-target) even in they appear smaller on screen.

Currently the element's touch target has no minimum which makes it harder to interact with on mobile devices.

We need to consider this while maintaining the responsive design.
This needs to apply to the thumb and track.

### Alternatives Considered

N / A

### Additional Context

_No response_

Start by locating the Story interactive component's thumb and track implementation, then inspect how its responsive sizing is applied. The work is done when both touch targets provide at least 48 x 48 px without breaking the responsive design; verify the result on mobile-sized layouts.

Written by the indexing model from the issue text.