Fonts without a "ẞ" are still displayed with "German" language filter

**Describe the issue**
According to https://github.com/googlefonts/lang/blob/main/Lib/gflanguages/data/languages/de_Latn.textproto ([#153](https://github.com/googlefonts/lang/pull/153)), ẞ is a required character and glyph for German support.

However, with the new language filter system on the website, if you select "German", you get fonts that do not have a ẞ.

**To Reproduce**
Select the language filter "German" and put an ẞ in Preview, like this: https://fonts.google.com/?preview.text=%E1%BA%9E&lang=de_Latn