Previously, the way we loaded the image hash for a given pet was to
navigate to `https://pets.neopets.com/cpn/<pet_name>/1/1.png`, but
*not* follow the redirect, and extract the image hash from the URL
where it redirected us to.
In this change, we refactor to use the AMFPHP RPC `PetService.getPet`
instead. I don't think it had this data last time I looked at it, but
now it does! Much prefer to use an actual RPC than our weird hacky
thing!
(We might also be able to use this call for other stuff, like
auto-labeling gender & mood for pet states, maybe?? That's in this data
too! We used to load petlookups for this, long long ago, before the
petlookup captchas got added.)