Fix service name test

[BenSurgisonGDS]

Allows the serverName in the config file to be changed and the change detected correctly when running the kit as a package.

[nataliecarey]

I want to keep looking into the reasons behind needing the two different selectors but I don't think that needs to hold this up.

[nataliecarey]

I've found the reason why it needs two different selectors (route cause of the issue). govuk-frontend has a template.njk that includes:

{% if params.serviceName %}
    {% if params.serviceUrl %}
      <a href="{{ params.serviceUrl }}" class="govuk-header__link govuk-header__service-name">
        {{ params.serviceName }}
      </a>
    {% else%}
      <span class="govuk-header__service-name">
        {{ params.serviceName }}
      </span>
    {% endif %}
    {% endif %}

Therefore the presence or absence of serviceUrl makes the difference. Running the kit as we currently recommend makes use of the layout.html which includes the header as:

{% block header %}
  {# Set serviceName in config.js. #}
  {{ govukHeader({
    homepageUrl: "/",
    serviceName: serviceName,
    serviceUrl: "/",
    containerClasses: "govuk-width-container"
  }) }}
{% endblock %}

(note the hard-coded forward slash as the URL)

I'm just trying to see why the same thing isn't happening when it's running as a module.