tests: Add retry metrics tests to ITOtelGoldenMetrics #671

Job	Run time
filter	1m 6s
showcase-clirr	5m 18s
build(25) except self-service clients	12m 53s
gapic-generator-java-bom	2m 10s
build(21) except self-service clients	12m 19s
build(8) except for gapic-generator-java	3m 54s
showcase (21)	5m 46s
unmanaged_dependency_check	7m 11s
showcase (17)	6m 2s
build (17)	14m 8s
dependency_analyzer_unit_test	1m 28s
build(8) for gapic-generator-java	11m 36s
showcase (11)	5m 52s
build (11)	10m 33s
showcase (25)	6m 3s
build(8) for showcase	2m 52s
	1h 49m 11s

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