Improve Debuggability in UTs of Trial Controller

[Electronic-Waste]

What you would like to be added?

Use the propagated gomega instance in replace of func() bool, like code here:

katib/pkg/controller.v1beta1/trial/trial_controller_test.go

Lines 303 to 314 in bc09cfd

	// Expect that Trial status is succeeded with "false" status and "metrics unavailable" reason.
	// Metrics unavailable because GetTrialObservationLog returns "unavailable".
	g.Eventually(func() bool {
	if err = c.Get(ctx, trialKey, trial); err != nil {
	return false
	}
	return trial.IsMetricsUnavailable() &&
	len(trial.Status.Observation.Metrics) > 0 &&
	trial.Status.Observation.Metrics[0].Min == consts.UnavailableMetricValue &&
	trial.Status.Observation.Metrics[0].Max == consts.UnavailableMetricValue &&
	trial.Status.Observation.Metrics[0].Latest == consts.UnavailableMetricValue
	}, timeout).Should(gomega.BeTrue())

Why is this needed?

As @tenzen-y described in #2394 (comment), it will improve the debuggability of the UTs.

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[Electronic-Waste]

/area testing
/good-first-issue
/remove-label lifecycle/needs-triage

[google-oss-prow]

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In response to this:

/area testing
/good-first-issue
/remove-label lifecycle/needs-triage

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[Electronic-Waste]

/assign