[web] add generated js code and flow types for identity_authenticated.proto

Summary:
Modify the generated files to add @generated and @flow annotations, convert the ts types to flow types, and fix import paths

Depends on D9793

Test Plan: used the generated IdentityClientServicePromiseClient in identity-auth-client.cjs to call getKeyserverKeys. got back my local keyserver's keys

Reviewers: ashoat

Reviewed By: ashoat

Subscribers: tomek, wyilio

Differential Revision: https://phab.comm.dev/D9807