ref(spooler): Remove use of legacy project cache #16963

Job	Run time
Lint Rust Default Features	1m 20s
Lint	2m 57s
Setup build metadata	1s
Test (macos-latest)	2m 4s
Test All Features (ubuntu-latest)	3m 21s
Test (windows-latest)	5m 28s
Integration Tests	6m 3s
Test Python	47s
Build Relay Binary (relay, x86_64-unknown-linux-gnu)	5m 56s
Build Docker Image	1s
Publish Relay to DockerHub	1s
Upload build artifacts to gocd	1s
Publish Relay to GCR	1s
self-hosted-end-to-end	1s
Sentry-Relay Integration Tests	1s
	28m 3s

Provide feedback