[native] display alert if register via SIWE fail

Summary:
Context in ENG-2543

Test Plan: Make sure keyserver will throw any error, register via SIWE, check if alert is visible and after click will navigate to login modal.

Reviewers: tomek, atul, ashoat

Reviewed By: ashoat

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D6069