perf(buffer): Move system check to precondition #16420

Job	Run time
Lint	3m 35s
Lint Rust Default Features	1m 17s
Test (macos-latest)	2m 26s
Test All Features (ubuntu-latest)	3m 50s
Test (windows-latest)	4m 33s
Setup build metadata	1s
Integration Tests	8m 15s
Test Python	47s
Build Relay Binary (relay, x86_64-unknown-linux-gnu)	7m 29s
Build Docker Image (relay)	40s
Sentry-Relay Integration Tests	13m 20s
Publish Relay to DockerHub	0s
self-hosted-end-to-end	14m 40s
Upload build artifacts to gocd	0s
Publish Relay to GCR	0s
	1h 0m 53s

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