feat: add one-tap auth trigger #trivial

[brainbicycle]

The type of this PR is: Feature

This PR resolves DI-291

Description

• adds one-tap as an AuthTrigger to differentiate from regular google sign in
• adds context_page_path in auth events to capture page auth started on

https://artsy.slack.com/archives/C05EEBNEF71/p1778881199224469?thread_ts=1778874112.044779&cid=C05EEBNEF71

PR Checklist (tick all before merging)

• If I've added a new file to the tree I've exported it from the common index.ts
• I've added comments with examples for any new interfaces and ensured that they're in the docs
• No platform-specific terminology has been used outside of click and tap (platform is inferred by the DB storing events) - maybe?

[xander-pero]

AFAIK context_page_path is actually something we already get on all our events based on the default web set up. I'm not sure how this works on the backend, but I see this firing within all the payloads for track events and is also present on the table. So just the AuthTrigger change is necessary!

[artsyit]

🚀 PR was released in v4.355.0 🚀