Add explicit dependency on grpc-core #156

Job	Run time
deploy / setup	4s
deploy / Build main (JDK 21)	5m 4s
deploy / Build main (JDK 25)	23m 1s
deploy / Build main (JDK 17)	9m 56s
deploy / Trigger CI for non-default branches	-1s
	38m 4s

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