file_validate_extensions() removed in D11

removed deprecated function replaced with file,validator service

With this patch I'm getting

TypeError: Drupal\google_analytics_reports_api\Form\GoogleAnalyticsReportsApiAdminSettingsForm::__construct(): Argument #6 ($file_validator) must be of type Drupal\file\FileValidatorInterface, Drupal\file\Validation\FileValidator given

Changing the use from
use Drupal\file\FileValidatorInterface;
to
use Drupal\file\Validation\FileValidatorInterface;

fixes the error.

Fix attached for D11

legitimate needed change.
Please, create an MR to merge it directly.