fix: use dynamic tracer name instead of hardcoded gax-java #224

Job	Run time
filter	1m 1s
dependency_analyzer_unit_test	1m 33s
build(8) for gapic-generator-java	11m 14s
build(21) except self-service clients	12m 16s
showcase-clirr	5m 2s
build (17)	14m 16s
showcase (25)	9m 47s
gapic-generator-java-bom	2m 32s
build(25) except self-service clients	12m 30s
build (11)	13m 54s
build(8) for showcase	9m 22s
unmanaged_dependency_check	8m 3s
build(8) except for gapic-generator-java	4m 17s
showcase (21)	10m 16s
showcase (11)	9m 44s
showcase (17)	9m 40s
	2h 15m 27s

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