fix: index route not detected if using folder

[suciptoid]

Fix flat routes when using folder as _index/routes.jsx

Example:
Throw error: Path "/:invoice" defined by route "$invoice._index/route" conflicts with route "$invoice/route" with route :

/routes/$invoice/route.tsx <-- layout
/routes/$invoice/_index/route.tsx

also close this issue

Closes: #5490

• Docs
• Tests

Testing Strategy:

[changeset-bot]

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Latest commit: ef20baa

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[mcansh]

thanks for the PR, this is resolved by #5459 :)

<Routes>
  <Route file="root.tsx">
    <Route path=":invoice" file="routes/$invoice/route.tsx">
      <Route index file="routes/$invoice/_index/route.tsx" />
    </Route>
  </Route>
</Routes>

[github-actions]

🤖 Hello there,

We just published version v0.0.0-nightly-aecf731-20230222 which involves this issue. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!