🐛 fix: Optimize requests without historical messages

[sxjeru]

💻 变更类型 | Change Type

• ✨ feat
• 🐛 fix
• ♻️ refactor
• 💄 style
• 👷 build
• ⚡️ perf
• 📝 docs
• 🔨 chore

🔀 变更说明 | Description of Change

当历史消息数设置为0时，应当不附带任何历史消息，请求中仅需包含本次发送的消息内容即可。

📝 补充信息 | Additional Information

close #4816
close #5154

[vercel]

@sxjeru is attempting to deploy a commit to the LobeHub Team on Vercel.

A member of the Team first needs to authorize it.

[lobehubbot]

👍 @sxjeru

Thank you for raising your pull request and contributing to our Community
Please make sure you have followed our contributing guidelines. We will review it as soon as possible.
If you encounter any problems, please feel free to connect with us.
非常感谢您提出拉取请求并为我们的社区做出贡献，请确保您已经遵循了我们的贡献指南，我们会尽快审查它。
如果您遇到任何问题，请随时与我们联系。

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.32%. Comparing base (9684c98) to head (fc10ae1).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff            @@
##             main    #5174    +/-   ##
========================================
  Coverage   92.32%   92.32%            
========================================
  Files         568      568            
  Lines       43204    43204            
  Branches     3978     3822   -156     
========================================
  Hits        39887    39887            
  Misses       3317     3317            

Flag	Coverage Δ
app	92.32% <100.00%> (ø)
server	97.66% <ø> (ø)

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