field_info_instances replacement

[mglaman]

https://git.drupalcode.org/project/drupal/-/blob/7.x/modules/field/field.info.inc#L569-607

Retrieves information about field instances.

function field_info_instances($entity_type = NULL, $bundle_name = NULL);

 * @return
 *   If $entity_type is not set, return all instances keyed by entity type and
 *   bundle name. If $entity_type is set, return all instances for that entity
 *   type, keyed by bundle name. If $entity_type and $bundle_name are set, return
 *   all instances for that bundle.

The function was replaced by the entity_field.manager service.

• No replacement for null $entity_type
• If $entity_type is set but no $bundle_name: \Drupal\Core\Entity\EntityFieldManagerInterface::getBaseFieldDefinitions
• Otherwise \Drupal\Core\Entity\EntityFieldManagerInterface::getFieldDefinitions

https://www.drupal.org/project/drupal/issues/2225739 is the issue where the function was removed for the field manager service.