Move `ContainedList`, `ContainedListItem` to stable

ContainedList and ContainedListItem have been flagged as ready for a review to move to stable. Based on the docs, the following criteria need to be met when moving a component from experimental to stable:

• All files have a copyright banner
• All components exported in src/index.js and should not be unstable_ prefixed
• Component has a label in the github repository
• Component should be documented on the website
  • Component should have a usage tab
  • Component should have a style tab
  • https://github.com/carbon-design-system/carbon-website/issues/3198
  • https://github.com/carbon-design-system/carbon-website/issues/3153
  • https://github.com/carbon-design-system/carbon-website/issues/3152
• For each component exported:
  • Component is written as a function declaration or uses forwardRef
  • Component has propTypes defined
    • Each prop type has a comment (used in storybook)
    • Prop types are as specific as needed, prefer PropTypes.shape over PropTypes.object if possible
  • Default props are listed as default args in the function definition (not in defaultProps)
    • Note: default props should be stable, in other words props like onClick = () => {} can cause re-renders since the function identity is not stable
  • Component has a story in <ComponentName>.stories.js
    • Component has an mdx document that follows our outline
    • mdx document coverages at least common use-cases and provides a prop table
    • Stories cover at least common use-cases
    • Stories may include a Playground story for controls
    • Stories should mirror intended usage of the component
  • Component has unit/integration tests written in RTL for testing the component API
  • Component is tested via VRT for at least the initial render state
  • Component is tested via AVT for at least the initial render state

Most of these above are complete already from the initial delivery in https://github.com/carbon-design-system/carbon/pull/11969 🎉

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Additionally I think we need to address the following in the storybook:

• On the playground story, hide className, actions, and children from the controls table
• Suggestions for updated story names
  • Following the storybook convention, it needs a “Default” story
    • Rename On page -> Default
  • Disclosed
  • With actions
  • With icons
  • With interactive items
  • With interactive items and actions
  • With list title decorator
  • Playground
  • would it be worthwhile to have a with layer story? I figure that might be a common use case
  • Could we reduce the repetition/duplication in the stories down to a single ContainedList with ContainedListChildren in each story?

[janhassel]

@tay1orjones Just opened a PR removing the disclosed variant demos from the sample stories: #12371

With this, I believe the list of storybook updates should be completed, correct?

[tay1orjones]

@janhassel Yeah this looks awesome! I just put up one final PR https://github.com/carbon-design-system/carbon/pull/12387 knocking out the rest of the checklist items (sans docs) and move it to stable 🎉