build(deps-dev): bump @storybook/theming in /dashboard

Bumps [@storybook/theming](https://github.com/storybookjs/storybook/tree/HEAD/code/lib/theming) from 7.5.3 to 8.1.6.
- [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/v8.1.6/code/lib/theming)

---
updated-dependencies:
- dependency-name: "@storybook/theming"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

dashboard/package.json

@@ -52,7 +52,7 @@
     "@storybook/preview-api": "^7.6.17",
     "@storybook/react": "^7.4.6",
     "@storybook/testing-library": "^0.2.2",
-    "@storybook/theming": "^7.5.3",
+    "@storybook/theming": "^8.1.6",
     "@testing-library/jest-dom": "^6.4.2",
     "@testing-library/react": "^14.1.2",
     "@types/cytoscape": "^3.19.16",