incorporate patch from 2864456 and remove unused reference to a theme file

includes/charts.pages.inc

@@ -218,7 +218,7 @@ function charts_cast_element_integer_values(&$element) {
 function charts_settings_form($form, $defaults = array(), $field_options = array(), $parents = array()) {
   // Ensure all defaults are set.
   $options = array_merge(charts_default_settings(), $defaults);
-  $form['#attached']['library'][] = array('charts', 'charts.admin');
+  $form['#attached']['library'][] = "charts/charts.admin";
 
   // Get a list of available chart libraries.
   $charts_info = charts_info();

src/Plugin/views/style/ChartsPluginStyleChart.php

@@ -6,7 +6,6 @@ use Drupal\core\form\FormStateInterface;
 use Drupal\Core\Render\Element;
 use Drupal\views\Plugin\views\style\StylePluginBase;
 
-\Drupal::moduleHandler()->loadInclude('charts', 'inc', 'charts.theme');
 \Drupal::moduleHandler()->loadInclude('charts', 'inc', 'includes/charts.pages');
 
 /**