Made change in PrometheusHealthIndicatorTest class

[vivek-opsmx]

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[vivek-opsmx]

Issue wrt commit :- PrometheusHealthIndicatorTest test case was failing due to

1. For downWhenHealthStatusesEmpty Test case error was org.mockito.exceptions.misusing.UnnecessaryStubbingException: Unnecessary stubbings detected.
2. For upWhenHealthStatusesAreAllUp The failure message was indicates that the test expected the health status to be UP for both "service1" and "service2," but the actual result was DOWN with the reason
   Solution :
3. for downWhenHealthStatusesEmpty added lenient()
4. the fix is it correctly handles the scenario where all health statuses are UP and constructs the Health object accordingly