chore: Improve traces e2e test outputs with FlatTrace #2121

Job	Run time
e2e (logs)	11m 17s
e2e-istio	9m 46s
e2e-dev (logs)	6m 26s
e2e (metrics)	13m 51s
e2e-dev (metrics)	6m 25s
e2e (traces)	10m 34s
e2e-self-mon (logs, healthy)	6m 38s
e2e-dev (traces)	6m 28s
e2e (telemetry)	7m 47s
e2e-self-mon (logs, backpressure)	9m 8s
e2e (max-pipeline)	6m 28s
e2e-self-mon (logs, outage)	10m 41s
e2e (telemetry-log-analysis)	13m 21s
e2e-self-mon (metrics, healthy)	7m 9s
e2e-self-mon (metrics, backpressure)	11m 39s
e2e-self-mon (metrics, outage)	12m 8s
e2e-self-mon (traces, healthy)	7m 14s
e2e-self-mon (traces, backpressure)	8m 40s
e2e-self-mon (traces, outage)	17m 10s
	3h 2m 50s

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