[Sat] Remove satellite-allowed polling mechanism in favor of callback

Now that there is a callback
(SatelliteManager.registerForCommunicationAllowedStateChanged), and
this callback fires once upon registration, we should be able to replace
the entire polling mechanism with the callback.

We'll still have the same general structure as before, where we wait
to know that satellite is supported and then we'll register with the
underlying service.

Note that we use a Lazily shared strategy here, since I think this is a
better tradeoff such that we're not un- and re- registering too often,
but we also never miss a callback.

Test: DeviceBasedSatelliteRepositoryImplTest
Bug: 348675732
Flag: com.android.internal.telephony.flags.oem_enabled_satellite_flag
Change-Id: I900b6583f7e655c6b441eee57ce298e0ef3e02dd