Create a device config indicates whether to send message in demo mode or not

It is needed to add a key to indicate whethere satellite datagram should be passed to satellite modem while in demo mode

Bug: 309346076
Test: atest SatelliteControllerTest DatagramDispatcherTest SatelliteManagerTestOnMockService
Change-Id: I860683d8245265436c6cda9254fe167737921346
2 files changed