Update README and vectorstore path for multi-modal template (#14473)

templates/rag-chroma-multi-modal/README.md

@@ -69,9 +69,9 @@ langchain app add rag-chroma-multi-modal
 
 And add the following code to your `server.py` file:
 ```python
-from rag_chroma import chain as rag_chroma_chain
+from rag_chroma_multi_modal import chain as rag_chroma_multi_modal_chain
 
-add_routes(app, rag_chroma_chain, path="/rag-chroma-multi-modal")
+add_routes(app, rag_chroma_multi_modal_chain, path="/rag-chroma-multi-modal")
 ```
 
 (Optional) Let's now configure LangSmith. 

templates/rag-chroma-multi-modal/rag_chroma_multi_modal/chain.py

@@ -101,7 +101,7 @@ def multi_modal_rag_chain(retriever):
 # Load chroma
 vectorstore_mmembd = Chroma(
     collection_name="multi-modal-rag",
-    persist_directory=str(Path(__file__).parent / "chroma_db_multi_modal"),
+    persist_directory=str(Path(__file__).parent.parent / "chroma_db_multi_modal"),
     embedding_function=OpenCLIPEmbeddings(
         model_name="ViT-H-14", checkpoint="laion2b_s32b_b79k"
     ),