Add ability to check if a HealthCheck.Result is healthy using a boolean

[sleberknight]

HealthCheckResultAssertions contains fluent isHealthy() and isUnhealthy() methods, which works in most cases.

But if you have a JUnit @ParameterizedTest to check various health check results, and all you care about is healthy or not, you can't. Instead, you must break these into separate tests.

For situations like this, it would be nice to be able to provide a boolean. For example, I want to be able to do this:

@ParameterizedTest
@CsvSource(textBlock = """
        200, OK, true
        201, OK, true
        202, OK, true
        400, WARN, false
        404, WARN, false
        500, CRITICAL, false
        """)
void shouldHaveExpectedResult(int statusCode, HealthStatus severity, boolean expectedHealthyValue) {
    var healthCheck = new new UrlHealthCheck(client, description, url, () -> true, kiwiEnvironment);
    server.enqueue(new MockResponse().setResponseCode(statusCode));
    assertThatHealthCheck(healthCheck)
            .hasHealthyValue(expectedHealthyValue)
            .hasDetail(HealthCheckResults.SEVERITY_DETAIL, severity.name());
}

In the above example code, hasHealthyValue accepts a boolean where true means healthy and false means unhealthy.