[chore][receiver/googlecloudpubsubreceiver/internal] Enable goleak ch… #15

Job	Run time
windows-unittest-matrix (receiver-0)	18m 36s
windows-unittest-matrix (receiver-1)	18m 38s
windows-unittest-matrix (processor)	14m 29s
windows-unittest-matrix (exporter)	25m 29s
windows-unittest-matrix (extension)	13m 2s
windows-unittest-matrix (internal)	16m 2s
windows-unittest-matrix (pkg)	12m 16s
windows-unittest-matrix (cmd)	23m 56s
windows-unittest-matrix (other)	22m 41s
windows-unittest	4s
	2h 45m 13s

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