Do not warn when selecting a text with comma

[veelenga]

When a text with comma is selected, the ember-cli-page-object produces a warning. Example:

// <fieldset>
//  <button>Lorem, Ipsum</button>
// </fieldset>

import { create, clickOnText } from 'ember-cli-page-object';

const page = create({
  clickOnButton: clickOnText('button')
});

page.clickOnButton('Lorem, Ipsum'); // Usage of comma separated selectors is deprecated in ember-cli-page-object

Fixes #518
Conflicts with #494

[ro0gr]

Thank you!

I'd like to avoid an extra method, by doing the check a bit earlier.

[ro0gr]

Excellent! Thanks!

[ro0gr]

just published your fix as 1.17.4