* Fix typo in GNSS_MODEL defination and usages for the UC6580
Correct the $CFGSYS init string for the UC6580 to init the receiver for:
GPS L1 & L5 + BDS B1I & B2a + GLONASS L1 + GALILEO E1 & E5a + SBAS
* Reduce GNSS serial traffic on Helted Wireless Tracker
Turn off GSV and NOTIFY __TXT messages as neither are
necessary to Meshtastic operation.