I am new to LLMs. I created a local RAG using Llamaindex with llama3 to load our documents and I am using ChromaDb to persist the embeddings. I am not clear on how do I specify a specific embedding model like BAAI/bge-small-en-v1.5 to be used to create embeddings instead of the default all-MiniLM-L6-v2 that Chroma DB uses. Here is my code: