[Improve] User cannot delete themselves

[zhangshenghang]

Purpose of this pull request

Check list

• Code changed are covered with tests, or it does not need tests for reason:
• If any new Jar binary package adding in your PR, please add License Notice according
  New License Guide
• If necessary, please update the documentation to describe the new feature. https://github.com/apache/seatunnel/tree/dev/docs

[arshadmohammad]

Server-side validation needs to be implemented.

[zhangshenghang]

Server-side validation needs to be implemented.

@arshadmohammad Has been modified and completed. PTAL