Remove json serialization annotation for `TableWriterNode.UpdateTarget`

[hantangwangd]

Description

UpdateTarget is a subclass of WriterTarget which is used coordinator-only. So there is no need to support serialization for it, referring to CreateName, InsertReference and DeleteHandle etc.

Motivation and Context

Remove unnecessary json serialization annotation

Impact

N/A

Test Plan

• Make sure the change do not affect existing test cases

Contributor checklist

• [x] Please make sure your submission complies with our development, formatting, commit message, and attribution guidelines.
• [x] PR description addresses the issue accurately and concisely. If the change is non-trivial, a GitHub Issue is referenced.
• [x] Documented new properties (with its default value), SQL syntax, functions, or other functionality.
• [x] If release notes are required, they follow the release notes guidelines.
• [x] Adequate tests were added if applicable.
• [x] CI passed.

Release Notes

== NO RELEASE NOTE ==