Dismiss missing permission check alerts in form validation methods

[mig42]

This PR dismisses the following security alerts:

• https://github.com/jenkinsci/plasticscm-plugin/security/code-scanning/1
• https://github.com/jenkinsci/plasticscm-plugin/security/code-scanning/2
• https://github.com/jenkinsci/plasticscm-plugin/security/code-scanning/3
• https://github.com/jenkinsci/plasticscm-plugin/security/code-scanning/4
• https://github.com/jenkinsci/plasticscm-plugin/security/code-scanning/5
• https://github.com/jenkinsci/plasticscm-plugin/security/code-scanning/6
• https://github.com/jenkinsci/plasticscm-plugin/security/code-scanning/7
• https://github.com/jenkinsci/plasticscm-plugin/security/code-scanning/8

Those were false positives. The method in CmTool performs the permissions check inside FormValidation.validateExecutable(), and the other methods only check whether the incoming values match the expectd format. They don't access sensitive information.

Testing done

Not needed. This PR only adds @SuppressWarnings annotations.

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue