Revert "[internal/otelarrow] Remove manual time.Sleep call" #41168

Job	Run time
setup-environment	1m 40s
arm-unittest-matrix (receiver-2)	8m 57s
arm-unittest-matrix (receiver-3)	6m 37s
arm-unittest-matrix (exporter-3)	5m 12s
arm-unittest-matrix (receiver-0)	5m 39s
arm-unittest-matrix (processor-0)	3m 54s
arm-unittest-matrix (exporter-1)	11m 4s
arm-unittest-matrix (exporter-2)	3m 44s
arm-unittest-matrix (processor-1)	4m 25s
arm-unittest-matrix (exporter-0)	3m 15s
arm-unittest-matrix (internal)	6m 56s
arm-unittest-matrix (connector)	4m 42s
arm-unittest-matrix (receiver-1)	7m 36s
arm-unittest-matrix (cmd-0)	4m 0s
arm-unittest-matrix (pkg)	5m 1s
arm-unittest-matrix (other)	4m 36s
arm-unittest-matrix (extension)	6m 15s
arm-unittest	2s
flakytests-generate-issues	0s
	1h 33m 35s

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