fix: display errors for oauth page

[crazywoola]

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Summary

close #38543

Screenshots

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Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran make lint && make type-check (backend) and cd web && pnpm exec vp staged (frontend) to appease the lint gods

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.34%. Comparing base (5a210cf) to head (785eed8).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #38546      +/-   ##
==========================================
- Coverage   85.34%   85.34%   -0.01%     
==========================================
  Files        5013     5013              
  Lines      265817   265817              
  Branches    50538    50538              
==========================================
- Hits       226863   226862       -1     
- Misses      34506    34507       +1     
  Partials     4448     4448              

Flag	Coverage Δ
dify-ui	94.61% <ø> (ø)
web	84.90% <ø> (-0.01%)	⬇️

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