getByName was not used anywhere in the code so that change is safe.

Please TEST this as i don't have a working Json setup in mqtt at the moment.

src/mesh/Channels.cpp

@@ -199,7 +199,7 @@ Channel &Channels::getByIndex(ChannelIndex chIndex)
 Channel &Channels::getByName(const char* chName)
 {
     for (ChannelIndex i = 0; i < getNumChannels(); i++) {
-        if (strcasecmp(channelFile.channels[i].settings.name, chName) == 0) {
+        if (strcasecmp(getGlobalId(i), chName) == 0) {
             return channelFile.channels[i];
         }
     }