feat(gax): Add error attributes to golden signal metrics. #17251

Job	Run time
package_name_check	1m 14s
gitignore_correctness	1m 18s
root-pom	1m 58s
group_id_check_for_maps_libraries	8m 50s
owlbot-yaml	1m 2s
owlbot-py	1m 21s
gapic-bom	1m 59s
generate-readme	1m 23s
	19m 5s

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