fix: support Menu fragment roots with router data attrs

[raashish1601]

Summary

• allow fragment-root components to fan out passthrough data-* props across multiple valid children
• add a shared render regression for multi-child fragments with router-style data-tsd-source
• add a Menu regression covering the Vite + TanStack Router crash from Menu element causing bug when used with Vite and Tanstack Router #3855

Testing

pm exec -- jest packages/@headlessui-react/src/utils/render.test.tsx packages/@headlessui-react/src/components/menu/menu.test.tsx --runInBand

pm exec -- prettier --check packages/@headlessui-react/src/utils/render.ts packages/@headlessui-react/src/utils/render.test.tsx packages/@headlessui-react/src/components/menu/menu.test.tsx

• git diff --check

Closes #3855

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