[Improve][CheckStyle] Remove useless 'SuppressWarnings' annotation of checkstyle.

[FlechazoW]

Remove useless 'SuppressWarnings' annotation of checkstyle.

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
• If you are contributing the connector code, please check that the following files are updated:
  1. Update change log that in connector document. For more details you can refer to connector-v2
  2. Update plugin-mapping.properties and add new connector information in it
  3. Update the pom file of seatunnel-dist
• Update the release-note.

[EricJoy2048]

LGTM, Please wait CI.

[Hisoka-X]

After we clean up these annotations, is there any benefit, what if someone adds corresponding annotations in the future?

[liugddx]

After we clean up these annotations, is there any benefit, what if someone adds corresponding annotations in the future?

This annotation is provided by checkstyle, we are not using it now and checkstyle should not be added automatically.

[Hisoka-X]

thanks, merging.