[landing] Bump @farcaster/auth-kit to 0.6.0

Summary: This adds support for redirecting back to Comm after the Farcaster login. It also seems to bump some timeouts.

Test Plan: Testing the Farcaster connection screen in a dev environment is kind of complicated, so I created this doc on Notion. I followed the instructions there for both physical iOS and Android devices

Reviewers: varun, will

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D13579