Show font’s main script in cards on fonts.google.com

I recently worked on an update of the Baloo 2 family. Since the fonts are arbitrarily named (not by their script name), there is no easy way to find the correct Baloo font for a specific script from the cards overview (which requires the knowledge of those fonts being for different scripts in the first place, maybe not a given for every user).

Please see this overview for reference: https://fonts.google.com/?query=baloo

Only once a script (rather: language) is chosen from the filters does the sample show up in the specific script.
If there is not already a dataset in place pointing out the dominant script of a font, I’m sure a heuristic can be conceived to calculate the font’s main script from its `subsets` definitions in `METADATA.pb` (see [here](https://github.com/google/fonts/blob/main/ofl/baloo2/METADATA.pb#L51)). Basically, all standard Latin-based subsets should be deleted and the remainder(s) constitute its main script. I haven't checked for other examples, but for the Baloo fonts that would work.

In case of several non-Latin scripts remaining thereafter, I think these should be mentioned in the cards as well.