fix: heltec v3: change gps enable pin

Author: oltaco

variants/heltec_v3/platformio.ini

@@ -25,7 +25,7 @@ build_flags =
   -D ENV_INCLUDE_GPS=1
   -D PIN_GPS_RX=47
   -D PIN_GPS_TX=48
-  -D PIN_GPS_EN=46
+  -D PIN_GPS_EN=26
 build_src_filter = ${esp32_base.build_src_filter}
   +<../variants/heltec_v3>
   +<helpers/sensors>