Make the run shell command more reliable for connectivity jobs.

Connectivity signals are asynchronous. It might take a few seconds after
the job is evaluated before the signal comes in, so wait a few seconds
if it makes sense before completing the run command so that tests can
have more reliable and consistent behavior.

Bug: 316435418
Test: atest CtsJobSchedulerTestCases:FlexibilityConstraintTest
Change-Id: I8072c86228e1a6112638d003c6d11a50dfc39010