Add `invalid_utf8` to reasons spans could be rejected #9536

Job	Run time
Run integration tests (test-e2e)	20m 24s
Run Unit Tests (test-with-cover-pkg)	3m 8s
Run integration tests (test-integration-poller)	10m 15s
Build	1m 47s
Run Unit Tests (test-with-cover-tempodb)	15m 24s
Benchmark	9m 26s
Run Unit Tests (test-with-cover-tempodb-wal)	11m 22s
Run integration tests (test-e2e-deployments)	13m 20s
Run Unit Tests (test-with-cover-others)	12m 9s
Build technical documentation	20s
Run integration tests (test-e2e-serverless)	7m 7s
Lint	3m 16s
Check jsonnet & tempo-mixin	47s
Vendor check	1m 28s
	1h 50m 13s

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