Remote media does not validate provider

Steps to reproduce

1. Create a media entity type with a remote video
2. Try to add a URL that does not match a configured oEmbed provider

Expected result

There should be an error message that the URL is not valid

Actual result

Unhandled exception:
InvalidArgumentException: Unknown provider 'LittleThings' in Drupal\media\OEmbed\ProviderRepository->get() (line 117 of /var/www/core/modules/media/src/OEmbed/ProviderRepository.php).