feat(gax): Add error attributes to golden signal metrics. #17205

Job	Run time
owlbot-py	1m 14s
generate-readme	1m 6s
package_name_check	1m 0s
owlbot-yaml	1m 2s
gapic-bom	1m 40s
root-pom	1m 44s
gitignore_correctness	1m 0s
group_id_check_for_maps_libraries	2m 0s
	10m 46s

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