Security: do not use litellm 1.82.7 and 1.82.8 (#13768)

### What problem does this PR solve?

See [issue](https://github.com/BerriAI/litellm/issues/24518) from
Litellm.

Upgraded from `1.81.15` to `1.82.6`, so RAGFlow is safe as always. 

### Type of change

- [x] Security

Co-authored-by: Jin Hai <haijin.chn@gmail.com>
Co-authored-by: Yingfeng <yingfeng.zhang@gmail.com>

pyproject.toml

@@ -145,8 +145,7 @@ dependencies = [
     #    "trio>=0.17.0,<0.29.0",
     #    "debugpy>=1.8.13",
     #    "click>=8.1.8",
-    #    "litellm>=1.74.15.post1",
-    #    "lark>=1.2.2",
+    "litellm~=1.82.0,!=1.82.7,!=1.82.8",
     #    "pip>=25.2",
     #    "imageio-ffmpeg>=0.6.0",
     #    "cryptography==46.0.3",