deps: Update opentelemetry-semconv to v1.29.0-alpha (#3635) #10145

Job	Run time
build (11)	15m 3s
build (17)	14m 41s
build(21) except self-service clients	13m 29s
build(8) except for gapic-generator-java	4m 30s
build(8) for gapic-generator-java	11m 3s
compatibility	1m 35s
dependency_analyzer_unit_test	16s
gapic-generator-java-bom	2m 4s
lint	30s
showcase (11)	4m 23s
showcase-clirr	0s
showcase (17)	4m 19s
showcase (21)	4m 28s
showcase (23)	4m 14s
unmanaged_dependency_check	9m 40s
	1h 30m 15s

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