Action does not work if flags are empty

[DefCon-007]

If no flags are set, the action fails with error code 255.

Steps to reproduce:

• Trying running the action without any custom flag

    - name: Run k6 test
      uses: grafana/run-k6-action@v1
      with:
        path: |
          ./k6/foundations/01.basic.js
        flags: --duration 5s

The reason seems to be an extra empty space before the path in case the flags are empty.