tests: Add retry metrics tests to ITOtelGoldenMetrics #17326

Job	Run time
owlbot-py	1m 11s
gitignore_correctness	1m 2s
root-pom	1m 41s
gapic-bom	1m 41s
package_name_check	1m 3s
group_id_check_for_maps_libraries	7m 53s
generate-readme	1m 5s
owlbot-yaml	1m 1s
	16m 37s

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