AG3335 GPS: Use NAVIC in India/Nepal, L1+L5 elsewhere. (#7413)

As determined by @b8b8 , enabling NAVIC meant the more modern L5 GPS
signal was not used (L1 GPS is always available).

NAVIC, India's GNSS, probably provides the best coverage in India and
the neighbouring region. However, outside of NAVIC's coverage area, L5
GPS is highly desirable.

This patch amends the AG3335-family GPS configuration to enable L5 GPS
coverage by default. If the Lora region is set to India or Nepal,
NAVIC will be enabled instead.

src/gps/GPS.cpp

@@ -643,8 +643,16 @@ bool GPS::setup()
             delay(250);
         } else if (IS_ONE_OF(gnssModel, GNSS_MODEL_AG3335, GNSS_MODEL_AG3352)) {
 
-            _serial_gps->write("$PAIR066,1,0,1,0,0,1*3B\r\n"); // Enable GPS+GALILEO+NAVIC
-
+            if (config.lora.region == meshtastic_Config_LoRaConfig_RegionCode_IN ||
+                config.lora.region == meshtastic_Config_LoRaConfig_RegionCode_NP_865) {
+                _serial_gps->write("$PAIR066,1,0,1,0,0,1*3B\r\n"); // Enable GPS+GALILEO+NAVIC
+                // GPS GLONASS GALILEO BDS QZSS NAVIC
+                //  1    0       1      0   0    1
+            } else {
+                _serial_gps->write("$PAIR066,1,1,1,1,0,0*3A\r\n"); // Enable GPS+GLONASS+GALILEO+BDS
+                // GPS GLONASS GALILEO BDS QZSS NAVIC
+                //  1    1       1      1   0    0
+            }
             // Configure NMEA (sentences will output once per fix)
             _serial_gps->write("$PAIR062,0,1*3F\r\n"); // GGA ON
             _serial_gps->write("$PAIR062,1,0*3F\r\n"); // GLL OFF