outlierdetection: Support health listener for ejection updates #13414

Job	Run time
vet-proto	19s
tests (vet, 1.22)	1m 20s
tests (extras, 1.23)	2m 49s
tests (tests, 1.23)	4m 26s
tests (tests, 1.23, -race)	5m 47s
tests (tests, 1.23, 386)	4m 54s
tests (tests, 1.23, arm64)	6m 45s
tests (tests, 1.22)	3m 43s
tests (tests, 1.23, -race, GRPC_EXPERIMENTAL_ENABLE_NEW_PICK_FIRST=true)	5m 51s
	35m 54s

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