[CPMS] Eliminating extra signal sent after shutdown happened

Test: atest CarPowerManagementServiceTest
Bug: 120958574
Change-Id: I9435bfbef33d6aababe2b1acb38ee32a446f636d
(cherry picked from commit e0f646c50e51e7c7e2033128efd4cc8c4978a6a1)
1 file changed