R1:30398b637182

Typeahead - filter typeaheads that the viewer can't see in typeahead debug tool

Summary:
Fixes T7255.

Note however that some datasources - notably user or project - don't implement the class thing in a clean way since multiple classes apply. For now, we just show these datasources to the user.

Also, I guess this could be done more efficiently by querying for all the applications at once via an application query? LMK if you want me to make that change.

Test Plan: loaded /typeahead/class/ and played with…