[JENKINS-74119] Remove inline onClick handlers in PowerShellBuildScript/config.jelly

[shlomomdahan]

JENKINS-74119

Very similar to #30

There is an onClick Handler on the Add Argument button however it looks like the functionality was previously removed. I removed it and it does not affect the functionality at all. relevant commit

Testing done

After Changes:

Screen.Recording.2024-12-05.at.6.36.25.PM.mov

1. Go to Manage Jenkins -> Managed Files -> Add new config file
2. Select 'Managed Powershell File` -> Save and submit.
3. Create Freestyle Project -> In Build Steps select: Execute Managed Powershell
4. Select the script create above -> Here you will see the code changed:
   i. view selected file
   ii. Add Argument

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