When creating an instance of AzureAISearchRetriever I do not need to pass an embedding function and my OpenAI dashboard shows no activity when invoking the retriever.

However, the documentation suggests that a vector search is run:
https://python.langchain.com/v0.2/docs/integrations/retrievers/azure_ai_search/

Am I missing something or does invoking the retriever just run a text search and no vector search?