Spring-ai GH-1623 fix typo for updating node in Neo4jVectorStore

• Resolve #1623
• Define DEFAULT_TRANSACTION_SIZE for the hardcoded batch size in the delete query

Comment From: tzolov

Hi @michael-simons , can you please review this PR?

Comment From: jitokim

@michael-simons thanks for review 😀

Comment From: markpollack

thanks for the contribution and the review!

merged in 1cdec7b6c3f7c15d0c1b741b9fce09be93105d86