fix: Apply bitmask to determine if ADR is valid

[barbeau]

GnssLogger currently uses a test of equality to 1 (GnssMeasurement.ADR_STATE_VALID) for GnssMeasurement.getAccumulatedDeltaRangeState() to determine if the ADR is valid for a particular measurement.

This no longer works with newer devices >= API 28, as the ADR is now a bitmask of the various constants listed at:
https://developer.android.com/reference/android/location/GnssMeasurement#constants_1

For example, the ADR state can be both ADR_STATE_HALF_CYCLE_RESOLVED logical OR'd with ADR_STATE_VALID, with gives you 1001 in binary or 9 in decimal. So this is a valid ADR state, but is not equal to 1.

You can see these valid ADR state values that aren't equal to 1 in the data from the Google "Smartphone Decimeter Challenge" here:
https://www.kaggle.com/google/android-smartphones-high-accuracy-datasets

This PR changes the GnssLogger code to correctly apply the bitmask to the GnssMeasurement.getAccumulatedDeltaRangeState() value to determine if it is a valid ADR state.

It also substitutes a check for an unknown ADR state by using the constant GnssMeasurement.ADR_STATE_UNKNOWN instead of just 0. Note that Lint incorrectly flags the use of this constant currently as an error - I've opened an issue on the Google issue tracker here about this:
https://issuetracker.google.com/issues/174553586