fix(webkit): centre a toast's leading glyph on its first title line

[gabriel-lisboa-azion]

Summary

• The toast's leading icon/spinner sits in a box one title line tall (h-[1lh] with text-label-md), so it centres on the first line of the title.
• Completes fix(webkit): stop wrapped toast titles overlapping and pin the glyph to line one #900, whose squashed diff only switched the row to items-start and never landed the line box its message describes.

How to test

1. Storybook → Components/Feedback/Toast → a one-line toast's icon is centred on the title, as before.
2. A toast with a long, wrapping title → the icon stays beside the first line.
3. A wrapping loading toast → the spinner sits on the first line (on main it sat beside the card's middle).
4. npx vitest run src/components/feedback/toast → all pass.

Notes

• Visible change for wrapped loading toasts only.