Fix for "has default channel" with empty channel name (#4430)

src/mesh/Channels.h

@@ -84,7 +84,7 @@ class Channels
     int16_t setActiveByIndex(ChannelIndex channelIndex);
 
     // Returns true if the channel has the default name and PSK
-    bool isDefaultChannel(const meshtastic_Channel &ch);
+    bool isDefaultChannel(ChannelIndex chIndex);
 
     // Returns true if we can be reached via a channel with the default settings given a region and modem preset
     bool hasDefaultChannel();
@@ -129,4 +129,4 @@ class Channels
 };
 
 /// Singleton channel table
-extern Channels channels;
+extern Channels channels;