deps: update googleapis/java-cloud-bom digest to ad905cc #7580

Job	Run time
build(21) except self-service clients	13m 20s
build(8) except for gapic-generator-java	4m 34s
build (11)	15m 5s
build (17)	14m 47s
build(8) for gapic-generator-java	11m 32s
compatibility	1m 35s
lint	22s
showcase (11)	4m 7s
showcase (17)	4m 19s
dependency_analyzer_unit_test	18s
showcase (21)	3m 53s
gapic-generator-java-bom	1m 52s
showcase-clirr	3m 21s
showcase-native	8m 41s
unmanaged_dependency_check	3m 42s
	1h 31m 28s

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