build(deps-dev): bump storybook from 7.6.20 to 7.6.21

Bumps [storybook](https://github.com/storybookjs/storybook/tree/HEAD/code/core) from 7.6.20 to 7.6.21.
- [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/v7.6.21/code/core)

---
updated-dependencies:
- dependency-name: storybook
  dependency-version: 7.6.21
  dependency-type: direct:development
...

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

Author: dependabot[bot]

apps/design-system/package.json

@@ -65,7 +65,7 @@
     "react-docgen-typescript": "^2.2.2",
     "react-docgen-typescript-plugin": "^1.0.5",
     "remark-gfm": "^3.0.1",
-    "storybook": "^7.6.20",
+    "storybook": "^7.6.21",
     "tailwind-config": "workspace:*",
     "tailwindcss": "^3.4.3",
     "ts-loader": "^9.4.3",