use new lora.use_preset bool (#1868)

src/mesh/Channels.cpp

@@ -218,7 +218,7 @@ const char *Channels::getName(size_t chIndex)
         // Per mesh.proto spec, if bandwidth is specified we must ignore modemPreset enum, we assume that in that case
         // the app fucked up and forgot to set channelSettings.name
 
-        if (config.lora.bandwidth != 0)
+        if (config.lora.use_preset)
             channelName = "Custom";
         else
             switch (config.lora.modem_preset) {