tests: Add retry metrics tests to ITOtelGoldenMetrics #18729

Job	Run time
enforcer	20m 1s
lint	41m 6s
changes	3s
generation-config-check	1m 41s
windows	2m 23s
gapic-libraries-bom	18m 36s
bulk-filter	1m 0s
split-units (sdk-platform-java, 17)	5m 4s
split-units (sdk-platform-java, 8)	4m 0s
split-units (sdk-platform-java, 11)	5m 30s
split-units (sdk-platform-java, 25)	4m 18s
split-units (sdk-platform-java, 21)	5m 10s
units (8)	40m 56s
units (11)	42m 30s
units (21)	33m 0s
units (25)	35m 31s
units (17)	32m 48s
	4h 53m 37s

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