Fix race condition in HIDL radio serivce test

Fixed the race condition between receiving onCurrentProgramInfoChanged
callback and updating mocked isCurrentOrSystemUser method called from
onCurrentProgramInfoChanged in cancel_forNonCurrentUser_doesNotCance
for HIDL HAL broadcast radio service tuner session unit test,

Bug: 302236983
Test: atest com.android.server.broadcastradio.hal2
Change-Id: I9218a611c57f6de2733b3e42e7bab935a5aa728c