chore: modify keycloak healthcheck endpoint for newer keycloak #1448

Job	Run time
test-suite (active-standby-kubernetes)	16m 45s
test-suite (api)	18m 10s
test-suite (deploytarget)	10m 27s
test-suite (features-kubernetes)	18m 22s
test-suite (features-kubernetes-2)	17m 28s
test-suite (features-variables)	13m 39s
test-suite (services)	12m 1s
test-suite (tasks)	11m 11s
	1h 58m 3s

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