text: Title: Improve Debuggability in UTs of Trial Controller
  Body: ### What you would like to be added?
  
  Use the propagated gomega instance in replace of `func() bool`, like code here:
  
  https://github.com/kubeflow/katib/blob/bc09cfd412da9220fcd13c5ff25a55fe86a6622f/pkg/controller.v1beta1/trial/trial_controller_test.go#L303-L314
  
  ### Why is this needed?
  
  As @tenzen-y described in https://github.com/kubeflow/katib/pull/2394#discussion_r1765558389, it will improve the debuggability of the UTs.
  
  ### Love this feature?
  
  Give it a 👍 We prioritize the features with most 👍