Sync user.geo to native layer

[krystofwoldrich]

Description

https://develop.sentry.dev/sdk/event-payloads/user/#geographical-location

The User interface has a new property geo that should be synced down to native layers.

Dart implementation: getsentry/sentry-dart#1393

[github-actions]

This issue has gone three weeks without activity. In another week, I will close it.

But! If you comment or otherwise update it, I will reset the clock, and if you label it Status: Backlog or Status: In Progress, I will leave it alone ... forever!

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"A weed is but an unloved flower." ― Ella Wheeler Wilcox 🥀