feat(spans): extract user.geo.geoscheme metrics #14890

Job	Run time
Setup build metadata	1s
Lint	1m 46s
Lint Rust Default Features	1m 6s
Test (macos-latest)	2m 51s
Test All Features (ubuntu-latest)	3m 47s
Integration Tests	13m 45s
Test (windows-latest)	5m 37s
Test Python	1m 5s
Build Relay Binary (relay, x86_64-unknown-linux-gnu)	7m 33s
Build Docker Image (relay)	1m 3s
Sentry-Relay Integration Tests	8m 24s
Publish Relay to DockerHub	0s
Upload build artifacts to gocd	0s
self-hosted-end-to-end	8m 26s
Publish Relay to GCR	0s
	55m 24s

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