feat(expo-example): configure and add magic link login

[andrascodes]

This PR is part of a stack created with Aviator. feat(expo-example): add export wallet on mobile #168 ➡️ feat(expo-example): configure and add magic link login #142 main

Closes FS-2088

Added magic link auth to the expo-example app and aligned it with the existing OTP to use the same hook to persist the data and the same input - resulting in a new EmailAuth component.
Made a change to how the app handles Redirect URIs as well: I added 1 Env Var to decide between using App Links or Deep Links. For App Links we derive the Redirect URIs from the RP_ID. Since for connecting a domain to an app a file needs to be served from the domain, it makes sense to use the same domain and RP_ID for Passkeys, Universal Links (both OAuth and Magic Link Redirect URIs) and Origin headers.
Setting up the new /verify-email callback involved adding a new intent in app.json as well, so the app opens when the right callback is opened from the email.