Investigate Starlight Details component

[melissahenderson]

When we first moved to Starlight, it didn't have a native component that allowed us to hide-collapse/show-expand content, so HJ created the Disclosure component for us.

Starlight now has a native Details component that conceptually works the same way.

We need to compare the two and if they are the same, or similar enough, then we should use the native Starlight component.

For this issue to be complete:

• [x] Compare the two components. If the home-grown component is better, then that's all we need to do. Otherwise...
• [ ] Identify all doc pages in all projects that use our Disclosure component. I don't think there's too many. One example is the Rafiki Webhooks page.
• [ ] Update those pages to use Starlight Details component.
• [ ] Create an issue in the docs-design-system repo letting Sarah know we don't need the Disclosure component anymore.
• [ ] Assign issue to Sarah.
• [ ] Update our style guide by deleting the /shared/disclosure/ page.

[melissahenderson]

During our team meeting today, we decided to use the native Starlight component.