feat(gax): Add error attributes to golden signal metrics. #17261

Job	Run time
owlbot-py	1m 19s
group_id_check_for_maps_libraries	8m 3s
gapic-bom	1m 49s
package_name_check	1m 11s
root-pom	1m 52s
generate-readme	1m 12s
gitignore_correctness	1m 10s
owlbot-yaml	1m 0s
	17m 36s

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