Pass minimum_components to field widget after_build

Problem/Motivation

The widgets passed in a field's widget after-build does not include minimum-components. This makes it so that developers need to push their own widget property to pass on the minimum components, even though an empty minimum-components property exists on the widget.

Steps to reproduce

function mymodule_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  foreach ($form_object->getEntity()->getFields() as $field) {
    $field_config = $field->getFieldDefinition();
    if (!($field_config instanceof FieldConfigInterface)) {
      continue;
    }
    $field_name = $field_config->getName();
    if (!isset($form[$field_name]) || !is_array($form[$field_name])) {
      continue;
    }

    if ($field_config->getType() === 'name') {
      if (empty($form[$field_name]['widget']) || !is_array($form[$field_name]['widget'])) {
        return;
      }

      // $field_config->getSettings()['minimum_components'] is typically available here.

      $form[$field_name]['widget']['#after_build'][] = '_mymodule_field_element_after_build';
    }
  }
}

function _mymodule_field_element_after_build(array $widget, FormStateInterface $form_state): array {
  // @todo Determine if minimum components is passed.
  if (empty($required_keys) || !is_array($required_keys)) {
    return $widget;
  }

  foreach (Element::children($widget) as $delta) {
    if (empty($widget[$delta]) || !is_array($widget[$delta])) {
      continue;
    }

    // $widget[$delta]['minimum_components'] is empty.
  }

  return $widget;
}

Proposed resolution

Supply a populated minimum-components to the field's widget.

Data model changes

The $widget[$delta]['minimum_components'] is populated in a field's widget after-build callback.