Remove unused EMBEDDER_PATH import from retriever.py

Agent-Logs-Url: https://github.com/Hitan547/agentic-corrective-rag/sessions/9fe79a82-a4b5-4130-ba4b-2a1d426aec19

Co-authored-by: Hitan547 <170419191+Hitan547@users.noreply.github.com>

retriever.py

@@ -4,7 +4,7 @@ import faiss
 from sentence_transformers import SentenceTransformer, CrossEncoder
 from config import (
     FAISS_INDEX_PATH, BM25_PATH, CHUNKS_PATH,
-    SOURCES_PATH, EMBEDDER_PATH
+    SOURCES_PATH
 )
 
 _faiss_index    = None