style: fix provider card dropdown menu seperator margin

[lyzno1]

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Summary

Screenshots

Before	After
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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 85.30%. Comparing base (f8d4761) to head (37aeabb).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #38422      +/-   ##
==========================================
- Coverage   85.30%   85.30%   -0.01%     
==========================================
  Files        4995     4995              
  Lines      264326   264322       -4     
  Branches    50141    50141              
==========================================
- Hits       225479   225475       -4     
  Misses      34429    34429              
  Partials     4418     4418              

Flag	Coverage Δ
dify-ui	94.75% <ø> (ø)
web	84.86% <100.00%> (-0.01%)	⬇️

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