Framework does not support integer choices

[almostSouji]

https://github.com/Naval-Base/yuudachi/blob/e398023952eeb2451af2c29884d9b848a5051985/packages/http/src/util/verifyRequest.ts#L16

Verification has to happen with the raw body, not the stringified JSON body. Discord sends "1.0" for integers, which is parsed to "1", failing the hash comparison.

Getting the raw body seems to be annoyingly complicated in fastify: https://www.npmjs.com/package/fastify-raw-body