Upgrade storybook version & fix accessibility panel

Context

The storybook dependencies are out-of-date.

Also noticed that the accessibility panel does not get rendered properly (keeps flickering)

Proposal

• Upgrade the storybook version in storybook/package.json
  • This might help with the accessibility panel
• Bonus: Make it such that the bot opens MR to update these dependencies frequently.

Note: Looking at the Storybook migration guide it looks like we will need to stay on version 7. Storybook 8.0 requires Vue 3.Because of that, it doesn't make sense to setup the renovate bot for now.

Resources

1. Here's the migration guide to Storybook 7.
2. Example MR of GitLab UI Storybook migration to v7