fix: revert pymumble protocol version patch that broke audio

Reporting version 1.5.0 to mumble-server caused it to expect the newer
audio frame format (terminator bit on opus length varint). pymumble
1.6.1 does not implement this, so the server silently dropped every
UDPTunnel audio packet. Revert to native 1.2.4 -- audio works, only
side effect is a cosmetic ChannelListener warning.

Also remove --cprofile from docker-compose command.

docker-compose.yml

@@ -18,4 +18,4 @@ services:
       - ./secrets:/app/secrets:ro,Z
     environment:
       - OPENROUTER_API_KEY
-    command: ["--verbose", "--cprofile"]
+    command: ["--verbose"]