Remove unnecessary audio channel 'Nch' differential

This was implemented to know the difference between services explicitly stating 5.1 channel audio, to a service explicitly stating 6.0 channel audio that is likely 5.1 channel layout.

However, since technically both are 6 channels, this is unnecessary and just causes complications.

devine/core/tracks/audio.py

@@ -87,10 +87,6 @@ class Audio(Track):
         if channels.upper() == "F801":
             return "5.1"
 
-        if str(channels).isdigit():
-            # This is to avoid incorrectly transforming channels=6 to 6.0, for example
-            return f"{channels}ch"
-
         try:
             return str(float(channels))
         except ValueError: