Bump storybook in the npm_and_yarn group across 1 directory

Bumps the npm_and_yarn group with 1 update in the / directory: [storybook](https://github.com/storybookjs/storybook/tree/HEAD/code/core).


Updates `storybook` from 8.6.14 to 8.6.15
- [Release notes](https://github.com/storybookjs/storybook/releases)
- [Changelog](https://github.com/storybookjs/storybook/blob/next/CHANGELOG.md)
- [Commits](https://github.com/storybookjs/storybook/commits/v8.6.15/code/core)

---
updated-dependencies:
- dependency-name: storybook
  dependency-version: 8.6.15
  dependency-type: direct:development
  dependency-group: npm_and_yarn
...

Signed-off-by: dependabot[bot] <support@github.com>

packages/ui/package.json

@@ -63,7 +63,7 @@
         "react-docgen": "^7.1.1",
         "react-dom": "^19.1.0",
         "react-router": "^7.6.0",
-        "storybook": "^8.6.13",
+        "storybook": "^8.6.15",
         "typescript": "~5.8.3",
         "typescript-eslint": "^8.30.1",
         "vite": "^6.4.1",