🐛 fix: Partial repair Doubao provider

[sxjeru]

💻 变更类型 | Change Type

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

🔀 变更说明 | Description of Change

由于 #5612 存在某些痛点，无法马上合并，可以先合并本 pr，解决部分问题。

• 临时修复环境变量添加的模型的连通性检测
• 允许新增带部署名的模型
• 默认禁用所有模型

目前存在环境变量添加模型和设置页添加模型的冲突问题，请只用一种方式添加，或者保证没有模型重复。

考虑该问题，先注释掉了所有预设的模型。

📝 补充信息 | Additional Information

目前豆包/火山方舟的正确使用方法可能是：

1. 利用环境变量添加模型和 apikey，举例 DOUBAO_MODEL_LIST=DeepSeek-R1>ep-20250211160940-rgsn6=DeepSeek-R1
DOUBAO_API_KEY=xxx-xxx
2. 前往设置页查看，应当确保“已启用”的模型为空；
   （由于 [Bug] 通过 xxx_MODEL_LIST 添加的模型无法在模型列表中显示 #6022 ）
3. 检查连通性，应当显示通过；
4. 虽然“已启用”的模型为空，但聊天页可显示通过环境变量添加的正确的模型。

或者完全不使用 DOUBAO_MODEL_LIST，而是只在设置页添加模型，应该也没问题，可以聊天，但连通性检查一定不会通过！

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.44%. Comparing base (be0d7f6) to head (408f163).
Report is 84 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6046      +/-   ##
==========================================
- Coverage   92.44%   92.44%   -0.01%     
==========================================
  Files         661      661              
  Lines       59979    59970       -9     
  Branches     3021     3020       -1     
==========================================
- Hits        55448    55439       -9     
  Misses       4531     4531              

Flag	Coverage Δ
app	92.44% <100.00%> (-0.01%)	⬇️
server	98.01% <ø> (ø)

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