outlierdetection: Support health listener for ejection updates (#7908) #13415

Job	Run time
vet-proto	20s
tests (vet, 1.22)	1m 20s
tests (extras, 1.23)	2m 52s
tests (tests, 1.23)	4m 16s
tests (tests, 1.23, -race)	5m 51s
tests (tests, 1.23, 386)	4m 53s
tests (tests, 1.23, arm64)	6m 36s
tests (tests, 1.22)	3m 39s
tests (tests, 1.23, -race, GRPC_EXPERIMENTAL_ENABLE_NEW_PICK_FIRST=true)	6m 3s
	35m 50s

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