Add missing dependencies

Problem/Motivation

When reinstalling a site with conditional_message from configuration the following error occurs in EntityTypeManager.php on line 150:

The "node_type" entity type does not exist.

ConditionalMessage::baseFieldDefinitions() uses node_type but the node dependency isn't defined so it might not be installed yet:

    // Get available content types.
    $all_types = \Drupal::entityTypeManager()
      ->getStorage('node_type')
      ->loadMultiple();
    foreach ($all_types as $machine_name => $content_type) {
      $content_types[$machine_name] = $content_type->get('name');
    }
    $fields['content_type_options'] = BaseFieldDefinition::create('list_string')
      ->setLabel(t('Content types'))
      ->setDescription(t('Select content types that will trigger the message'))
      ->setSettings([
        'allowed_values' => $content_types,
      ])
      ->setCardinality(FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED)
      ->setDisplayOptions('view', [
        'label' => 'above',
        'type' => 'string',
        'weight' => -7,
      ])
      ->setDisplayOptions('form', [
        'type' => 'options_buttons',
        'weight' => -7,
      ])
      ->setDisplayConfigurable('form', TRUE)
      ->setRequired(FALSE);

Proposed resolution

We should add a dependency to drupal:node.