DA-831: Update LangChain to use CouchbaseSearchVectorStore#8

ejscribner wants to merge 2 commits intomaincouchbase-examples/vector-search-nodejs:mainfrom

DA-831/update-langchain-use-search-vectorstorecouchbase-examples/vector-search-nodejs:DA-831/update-langchain-use-search-vectorstoreCopy head branch name to clipboard