fix moved imports for langchain 0.3

fiscal.py

@@ -3,10 +3,10 @@ from typing import Dict
 from langchain_huggingface import HuggingFaceEmbeddings, ChatHuggingFace, HuggingFaceEndpoint
 from langchain_community.vectorstores import Chroma
 from langchain_community.retrievers import BM25Retriever
-from langchain.retrievers import EnsembleRetriever
+from langchain_community.retrievers import EnsembleRetriever
 from langchain.chains import ConversationalRetrievalChain
 from langchain.memory import ConversationBufferMemory
-from langchain.prompts import PromptTemplate
+from langchain_core.prompts import PromptTemplate
 from langchain_core.documents import Document
 
 # ---------- Embeddings ----------