SIGN-7466 - removed apiUrl parameter

[volbobvol]

Testing done

• I tested the configuration with apiUrl parameter provided in the Jenkinsfile, to ensure that the plugin ignores the value. The plugin behaves as expected and reports that the apiUrl parameter is not supported.
• I also tested the case where the apiUrl parameter is not provided in the Jenkinsfile. In this scenario, the plugin correctly retrieves the value from the global configuration.

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