allows manual BLE pin even when device has display

also updates remaining variants to use default of
123456 instead of 0 for random pin

variants/heltec_v3/platformio.ini

@@ -107,7 +107,7 @@ build_flags =
   -D MAX_CONTACTS=100
   -D MAX_GROUP_CHANNELS=8
   -D DISPLAY_CLASS=SSD1306Display
-  -D BLE_PIN_CODE=0   ; dynamic, random PIN
+  -D BLE_PIN_CODE=123456   ; dynamic, random PIN
   -D BLE_DEBUG_LOGGING=1
   -D OFFLINE_QUEUE_SIZE=256
 ;  -D MESH_PACKET_LOGGING=1