fix LIGHTEN issue (#2806)

### What problem does this PR solve?


### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

api/apps/llm_app.py

 @login_required
 def list_app():
     self_deploied = ["Youdao","FastEmbed", "BAAI", "Ollama", "Xinference", "LocalAI", "LM-Studio"]
-    weighted = ["Youdao","FastEmbed", "BAAI"] if LIGHTEN else []
+    weighted = ["Youdao","FastEmbed", "BAAI"] if not LIGHTEN else []
     model_type = request.args.get("model_type")
     try:
         objs = TenantLLMService.query(tenant_id=current_user.id)

api/settings.py

 
     CHAT_MDL = default_llm[LLM_FACTORY]["chat_model"]
     EMBEDDING_MDL = default_llm["BAAI"]["embedding_model"]
-    RERANK_MDL = default_llm["BAAI"]["rerank_model"] if not LIGHTEN else ""
+    RERANK_MDL = default_llm["BAAI"]["rerank_model"]
     ASR_MDL = default_llm[LLM_FACTORY]["asr_model"]
     IMAGE2TEXT_MDL = default_llm[LLM_FACTORY]["image2text_model"]
 else:

rag/nlp/__init__.py

 
     for sec, pos in sections:
         add_chunk(sec, pos)
-        continue
-        s, e = 0, 1
-        while e < len(sec):
-            if sec[e] in delimiter:
-                add_chunk(sec[s: e + 1], pos)
-                s = e + 1
-                e = s + 1
-            else:
-                e += 1
-        if s < e:
-            add_chunk(sec[s: e], pos)
 
     return cks