Taxonomy dependency causes fatal error on config page

Using a Drupal 8 install without the Taxonomy module enabled:

1. Install the datalayer module
2. Navigate to /admin/config/search/datalayer
3. Fatal error:
   Error: Class 'Drupal\taxonomy\Entity\Vocabulary' not found in Drupal\datalayer\Form\DatalayerSettingsForm->buildForm() (line 128 of modules/contrib/datalayer/src/Form/DatalayerSettingsForm.php).

We should check if the Taxonomy module is enabled, I think this can be done using the following:

// Setup vocabs.
$v_options = [];
$moduleHandler = \Drupal::service('module_handler');
if ($moduleHandler->moduleExists('taxonomy')){
  $vocabs = Vocabulary::loadMultiple();
  foreach ($vocabs as $v) {
    $v_options[$v->id()] = $v->label();
  }
}
$datalayer_settings = $this->config('datalayer.settings');

This seemed to work, but I might have missed something.

I'm using 8.x-1.0-beta2, but might also be in other versions.