Merge branch 'autosize-js-perf' into 'master'

Make autosize fields more performant and remove broken autosize handle

See merge request !12532

app/assets/javascripts/behaviors/autosize.js

 import autosize from 'vendor/autosize';
-$(() => {
-  const $fields = $('.js-autosize');
-  $fields.on('autosize:resized', function resized() {
-    const $field = $(this);
-    $field.data('height', $field.outerHeight());
-  });
-
-  $fields.on('resize.autosize', function resize() {
-    const $field = $(this);
-    if ($field.data('height') !== $field.outerHeight()) {
-      $field.data('height', $field.outerHeight());
-      autosize.destroy($field);
-      $field.css('max-height', window.outerHeight);
-    }
-  });
-
-  autosize($fields);
-  autosize.update($fields);
-  $fields.css('resize', 'vertical');
+document.addEventListener('DOMContentLoaded', () => {
+  const autosizeEls = document.querySelectorAll('.js-autosize');
+  autosize(autosizeEls);
+  autosize.update(autosizeEls);
 });