feat(MessageLogModal): refactor modal structure and improve tab handling

[CodingOnStar]

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Summary

• Replaced floating modal implementation with a Dialog component for better accessibility and styling.
• Introduced a type guard for active tab validation, ensuring only valid tabs are set.
• Updated modal rendering logic to handle fixed and dynamic widths more effectively.
• Adjusted tests to reflect changes in modal behavior and structure.

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

❌ Patch coverage is 70.00000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.89%. Comparing base (a9bcec0) to head (fac2afc).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...eb/app/components/base/message-log-modal/index.tsx	70.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #36169      +/-   ##
==========================================
- Coverage   85.89%   85.89%   -0.01%     
==========================================
  Files        4454     4454              
  Lines      210844   210847       +3     
  Branches    39450    39451       +1     
==========================================
  Hits       181104   181104              
- Misses      26516    26519       +3     
  Partials     3224     3224              

Flag	Coverage Δ
dify-ui	94.40% <ø> (ø)
web	86.60% <70.00%> (-0.01%)	⬇️

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