You were a cop where the court time was a PART of a your job. TSA is no different than a grocery store clerk. Sure if there was a robbery of the store, the store may cover their time, but if there was an altercation between two customers and the employee was a witness, I'd think the employee would be on their own when called to testify.
If TSA is directly in involved - maybe. Otherwise, they should not be paid, it'd be yet another facet that would get abused