[lib] handle policies_not_accepted error on client

Summary:
Catch policies_not_accepted ServerError on both HTTP request and WebSocket call and dispatch redux action which containing information that policies needs to be acknowledged

Context in ENG-2363.

Test Plan: Connect to keyserver from account without accepted policies and check if action was properly dispatched after interaction with keyserver on both mobile/web (testing both HTTP and WebSocket connection).

Reviewers: tomek, atul

Reviewed By: tomek

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D5827