[lib] Use httpMessageUserInfosHandler

Summary:
issue: ENG-7821
When I tried using endpointValidators in callSingleKeyserverEndpoint it created import cycles which are hard to fix. An explenation can be found here.
The bottom line is that I cannot import lib/types/validators/endpoint-validators.js from lib/keyserver-conn/call-single-keyserver-endpoint.js. So my workaroud is for lib/keyserver-conn/call-single-keyserver-endpoint.js to expose a function that lets some other place in the code insert the handler to it.

Test Plan: Tested that both web and native apps can be run and no errors are thrown. Tested that the handler correctly extracts user ids from http messages.

Reviewers: tomek, kamil, ashoat

Reviewed By: ashoat

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D12073