Speed-Space chart is partially hidden in story book + awkward blacks margins

[Castavo]

What happened?

Enregistrement.de.l.ecran.2024-09-26.160325.mp4

I can't see the left part, it's eaten by the box. I think this weird behavior is reflected in OSRD: when zooming in or out, the component's width doesn't change
Also, it feels like the black borders shouldn't be there

What did you expect to happen?

I expect the component to take up the width of the box and not flow out.

How can we reproduce it (as minimally and precisely as possible)?

1. Go to https://openrailassociation.github.io/osrd-ui/?path=/docs/speedspacechart-rendering--docs
2. Witness

On which environments the bug occurs?

Deployed Storybook

On which browser the bug occurs?

Firefox