Run EphemeralTest#testGetSearchableInfo in presubmit when changing PackageMonitorCallbackHelper

Does't catch the issue in presubmit. Because this may be impacted by
the logic in PackageMonitorCallbackHelper. For someone who doesn't
familiar with the topic may miss it. Try to add into presubmit. The
running time is short, it should be acceptable to add into presubmit.

Bug: 289797357
Test: TH result

Change-Id: I887686a7699965361758c189f3a6f87e0b866c66