[scraper/processscraper] Fix TestScrapeMetrics_MuteErrorFlags failures on windows and darwin #61917

Job	Run time
windows-unittest-matrix (receiver-0)	20m 16s
windows-unittest-matrix (receiver-1)	16m 59s
windows-unittest-matrix (processor)	13m 30s
windows-unittest-matrix (exporter)	23m 54s
windows-unittest-matrix (extension)	14m 17s
windows-unittest-matrix (internal)	16m 59s
windows-unittest-matrix (pkg)	10m 28s
windows-unittest-matrix (cmd)	19m 39s
windows-unittest-matrix (other)	15m 56s
windows-unittest	3s
	2h 32m 1s

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