[native] Create native/facts/alchemy.json file in release GitHub Actions

Summary: Context in ENG-2589. We need the Alchemy key in the mobile app so we can do ENS lookups.

Test Plan: Test plan described here: https://linear.app/comm/issue/ENG-2589#comment-e9f23909

Reviewers: atul

Reviewed By: atul

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D6260