Workflow should only run for issues that have the `new contribution` label

The `if` condition for `new contribution` in `issue_to_pr.yml` is incorrectly placed at the **workflow** level. 

It should be moved to the **job** level to properly control job execution. See: "[Using conditions to control job execution](https://docs.github.com/en/actions/writing-workflows/choosing-when-your-workflow-runs/using-conditions-to-control-job-execution)".