New trait to create file upload validators from file field settings

A new trait with method to create file upload validators from settings has been added Drupal\file\Validation\FileValidatorSettingsTrait::getFileUploadValidators()

Example usage

use FileValidatorSettingsTrait;

// Given a file field definition:
$settings = $field_definition->getSettings();

// Get an array of validators suitable for passing to the file validator:
$validators = $this->getFileUploadValidators($settings);

// Validate a file entity:
$violations = \Drupal::service('file.validator')->validate($file, $validators);