Improved output in case if no violations found

Fix the use case of no output in case of no violations were found.
Old behavior:

        prettyPrintAxeReport({
            violations: [],
            url: 'www.example.com',
        });

no output
New behavior:

        prettyPrintAxeReport({
            violations: [],
            url: 'www.example.com',
        });

Outputs:
No accessibility violations were detected for the www.example.com