[Bugfix]: write nest json schema

[Jin-H]

What type of PR is this：

• [x] BugFix
• [ ] Feature
• [ ] Enhancement
• [ ] Refactor
• [ ] UT
• [ ] Doc
• [ ] Tool

Which issues of this PR fixes ：

Fixes #

Problem Summary(Required) ：

Checklist:

• [ ] I have added test cases for my bug fix or my new feature
• [ ] This pr will affect users' behaviors
• [ ] This pr needs user documentation (for new or modified features or behaviors)
• [ ] I have added documentation for my new feature or new function

[Jin-H]

junit error will be fixed in https://github.com/StarRocks/starrocks-connector-for-apache-flink/pull/336

[Jin-H]

I'll add some test and reproduce step later.