Remove narrative UI docs from Storybook

[pavithraes]

Description

Since we've migrated all narrative docs to https://conda.store/conda-store-ui/introduction, removing it from the Storybook site.

Moving forward, Storybook can be used for the component docs alone :)

Pull request checklist

• [x] Did you test this change locally?
• [x] Did you update the documentation (if required)?
• [ ] Did you add/update relevant tests for this change (if required)?

Additional information