fix: Update default Otel Attribute from method_name to method #7055

Job	Run time
build(21) except self-service clients	11m 52s
build (11)	13m 30s
build(8) for gapic-generator-java	9m 38s
build (17)	12m 39s
lint	36s
compatibility	1m 38s
build(8) except for gapic-generator-java	4m 10s
showcase (11)	4m 6s
showcase-native	8m 18s
showcase (17)	4m 9s
dependency_analyzer_unit_test	23s
gapic-generator-java-bom	2m 34s
showcase-clirr	3m 4s
unmanaged_dependency_check	4m 41s
	1h 21m 18s

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