Filename and locale don't match in news_article example

[ChrisBAshton]

See https://github.com/alphagov/publishing-api/blob/main/content_schemas/examples/news_article/frontend/news_article_news_story_translated_arabic.json#L6

Filename: news_article_news_story_translated_arabic.json
Locale: ur

ur is Urdu, not Arabic. Either the filename should be updated to news_article_news_story_translated_urdu.json(along with the equivalent tests in places like government-frontend), or the locale and file contents should be updated.