roll back rerank topn setting (#11297)

api/.env.example

 
 CREATE_TIDB_SERVICE_JOB_ENABLED=false
 
-RETRIEVAL_TOP_N=0

api/configs/feature/__init__.py

         default=30,
     )
 
-    RETRIEVAL_TOP_N: int = Field(description="number of retrieval top_n", default=0)
-
 
 class WorkspaceConfig(BaseSettings):
     """

api/core/rag/datasource/retrieval_service.py

 
 from flask import Flask, current_app
 
-from configs import DifyConfig
 from core.rag.data_post_processor.data_post_processor import DataPostProcessor
 from core.rag.datasource.keyword.keyword_factory import Keyword
 from core.rag.datasource.vdb.vector_factory import Vector
                 query=query,
                 documents=all_documents,
                 score_threshold=score_threshold,
-                top_n=DifyConfig.RETRIEVAL_TOP_N or top_k,
+                top_n=top_k,
             )
 
         return all_documents
                                 query=query,
                                 documents=documents,
                                 score_threshold=score_threshold,
-                                top_n=DifyConfig.RETRIEVAL_TOP_N or len(documents),
+                                top_n=len(documents),
                             )
                         )
                     else:
                                 query=query,
                                 documents=documents,
                                 score_threshold=score_threshold,
-                                top_n=DifyConfig.RETRIEVAL_TOP_N or len(documents),
+                                top_n=len(documents),
                             )
                         )
                     else: