[receiver/opencensus] Do not report error message on clean shutdown (… #17206

Job	Run time
arm-unittest-matrix (receiver-0)	5m 12s
arm-unittest-matrix (receiver-1)	6m 38s
arm-unittest-matrix (receiver-2)	8m 32s
arm-unittest-matrix (receiver-3)	6m 10s
arm-unittest-matrix (processor-0)	3m 23s
arm-unittest-matrix (processor-1)	4m 24s
arm-unittest-matrix (exporter-0)	3m 15s
arm-unittest-matrix (exporter-1)	9m 32s
arm-unittest-matrix (exporter-2)	4m 3s
arm-unittest-matrix (exporter-3)	4m 55s
arm-unittest-matrix (extension)	5m 5s
arm-unittest-matrix (connector)	4m 0s
arm-unittest-matrix (internal)	6m 23s
arm-unittest-matrix (pkg)	3m 35s
arm-unittest-matrix (cmd-0)	1m 20s
arm-unittest-matrix (cmd-1)	1m 51s
arm-unittest-matrix (other)	4m 25s
arm-unittest	1s
	1h 22m 44s

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