revert embedding model

stores/chroma.py

@@ -5,7 +5,7 @@ from langchain_chroma import Chroma
 class ChromaDB:
     def __init__(self, embeddings):
         self._persistent_directory = "embeddings"
-        model_name = "models/text-embedding-004"
+        model_name = "sentence-transformers/all-mpnet-base-v2"
         model_kwargs = {'device': 'cpu'}
         encode_kwargs = {'normalize_embeddings': False}
         self.embeddings = embeddings