feat(gax): Add error attributes to golden signal metrics. (#12564) #625

Job	Run time
filter	1m 6s
build(21) except self-service clients	12m 13s
build(8) for gapic-generator-java	10m 38s
build(8) for showcase	7m 41s
build (17)	13m 27s
build(8) except for gapic-generator-java	3m 53s
build (11)	13m 42s
showcase (11)	11m 22s
dependency_analyzer_unit_test	37s
showcase (21)	10m 21s
unmanaged_dependency_check	10m 11s
gapic-generator-java-bom	2m 5s
build(25) except self-service clients	12m 12s
showcase (25)	10m 30s
showcase (17)	10m 58s
showcase-clirr	0s
	2h 10m 56s

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