Enable LNA by default for Heltec v4.3 (#9906)

It should only be disabled by users that have problems with it.

src/mesh/NodeDB.cpp

@@ -569,7 +569,7 @@ void NodeDB::installDefaultConfig(bool preserveKey = false)
     config.lora.override_duty_cycle = false;
     config.lora.config_ok_to_mqtt = false;
 #if HAS_LORA_FEM
-    config.lora.fem_lna_mode = meshtastic_Config_LoRaConfig_FEM_LNA_Mode_DISABLED;
+    config.lora.fem_lna_mode = meshtastic_Config_LoRaConfig_FEM_LNA_Mode_ENABLED;
 #else
     config.lora.fem_lna_mode = meshtastic_Config_LoRaConfig_FEM_LNA_Mode_NOT_PRESENT;
 #endif