Wizard test fails when GPS mode screen is present

[Brendan Donegan]

On releases which have HERE maps installed there will be an extra screen in the wizard to choose the GPS mode (GPS only, All or None). Currently the way the wizard test is written does not consider this eventuality, so we get:

Traceback (most recent call last):
  File "/tmp/adt-run.M5Co1A/build.Ngp/real-tree/ubuntu_system_tests/tests/test_settings_wizard.py", line 149, in test_complete_settings_wizard
    self.config[KEY_WIFI_PASSWORD])
  File "/tmp/adt-run.M5Co1A/build.Ngp/real-tree/ubuntu_system_tests/tests/test_settings_wizard.py", line 101, in _test_wifi_connect_page
    return wifi_connect_page.continue_()
  File "/tmp/adt-run.M5Co1A/deps/usr/lib/python3/dist-packages/autopilot/logging.py", line 46, in inner
    return f(instance, *args, **kwargs)
  File "/tmp/adt-run.M5Co1A/build.Ngp/real-tree/ubuntu_system_tests/helpers/unity8/settings_wizard.py", line 389, in continue_
    return get_wizard(self).get_reporting_page()
  File "/tmp/adt-run.M5Co1A/build.Ngp/real-tree/ubuntu_system_tests/helpers/unity8/settings_wizard.py", line 67, in get_reporting_page
    objectName='reportingPage', visible='True')
  File "/tmp/adt-run.M5Co1A/deps/usr/lib/python3/dist-packages/autopilot/introspection/dbus.py", line 295, in wait_select_single
    return self.select_single(type_name, **kwargs)
  File "/tmp/adt-run.M5Co1A/deps/usr/lib/python3/dist-packages/autopilot/introspection/dbus.py", line 244, in select_single
    raise StateNotFoundError(type_name_str, **kwargs)
autopilot.exceptions.StateNotFoundError: Object not found with name '*' and properties {'visible': 'True', 'objectName': 'reportingPage'}.

On e.g. 'ubuntu-touch/rc-proposed/bq-aquaris.en-proposed' channel