fix(docs): Fix broken Edge Functions 401 troubleshooting guide link (#46355)

## I have read the
[CONTRIBUTING.md](https://github.com/supabase/supabase/blob/master/CONTRIBUTING.md)
file.

YES

## What kind of change does this PR introduce?

- Fix broken link
- Affected page https://supabase.com/docs/guides/functions/auth-headers
- Currently links to
https://supabase.com/docs/troubleshooting/edge-function-401-error-response
which 404s
- Correct link
https://supabase.com/docs/guides/troubleshooting/edge-function-401-error-response

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## Summary by CodeRabbit

* **Documentation**
* Updated troubleshooting guide reference link for Edge Function 401
error responses to point to the correct location.

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apps/docs/content/guides/functions/auth-headers.mdx

@@ -40,4 +40,4 @@ Set the flag per function in `supabase/config.toml`:
 verify_jwt = false
 ```
 
-For 401 failure modes and how to diagnose them, see [Edge Function 401 error response](/docs/troubleshooting/edge-function-401-error-response).
+For 401 failure modes and how to diagnose them, see [Edge Function 401 error response](/docs/guides/troubleshooting/edge-function-401-error-response).