[identity] [4/n] Return ConnectionInitializationResponse on identity search auth

Summary:
Return ConnectionInitializationResponse with status of identity search authentication

Depends on D10847

Test Plan: Successfully ran on local dev and tested authentication responses.

Reviewers: varun, bartek

Reviewed By: bartek

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D10848