feat: Allow Adding Client Level Attributes to MetricsTracerFactory #6926

Job	Run time
build(21) except self-service clients	11m 41s
build (11)	13m 9s
build(8) except for gapic-generator-java	4m 14s
build (17)	12m 53s
build(8) for gapic-generator-java	9m 34s
compatibility	1m 38s
dependency_analyzer_unit_test	15s
gapic-generator-java-bom	1m 43s
showcase (11)	4m 26s
showcase-clirr	2m 52s
showcase (17)	4m 4s
lint	27s
showcase-native	8m 33s
unmanaged_dependency_check	5m 38s
	1h 21m 7s

Provide feedback