Fix QdrantVectorDB to use custom embedding_function when provided, de…

…faulting to FastEmbedEmbeddingFunction() otherwise (#3396)

Co-authored-by: Li Jiang <[email protected]>

autogen/agentchat/contrib/vectordb/qdrant.py

@@ -93,7 +93,7 @@ def __init__(
             kwargs: dict | Additional keyword arguments.
         """
         self.client: QdrantClient = client or QdrantClient(location=":memory:")
-        self.embedding_function = FastEmbedEmbeddingFunction() or embedding_function
+        self.embedding_function = embedding_function or FastEmbedEmbeddingFunction()
         self.collection_options = collection_options
         self.content_payload_key = content_payload_key
         self.metadata_payload_key = metadata_payload_key