Prevent redundent command to modem for startSendingNtnSignalStrength

SatelliteController was flooding modem with a command.
Therefore a cache was intoduced to compare the current modem state with
the expected state and to ignore command that match.

Bug: 308838372
Test: Manually test and verify via tracking log.

Change-Id: Icf4eba2afaffe098e7193d5c21de666882516ba9