Setting clock flags for GPS clock

Full bias nanosecond flag is now set correctly for
legacy GpsData (vs. modern GnssData) implementations
of gps.h measurements, going through default GNSS
HAL implementation.

Change-Id: Iec8f03994b6d9e509221e1323b54dc997319fccc
Fixes: 64482271
Test: Before/after on device with GnssLogger