lnwatcher: do not listen to 'fee' and 'network_updated' events.

Only blockchain changes are relevant for breach remedy.

electrum/lnwatcher.py

@@ -175,14 +175,6 @@ class LNWatcher(Logger, EventListener):
         self.adb.add_address(address)
         self.callbacks[address] = callback
 
-    @event_listener
-    async def on_event_fee(self, *args):
-        await self.trigger_callbacks()
-
-    @event_listener
-    async def on_event_network_updated(self, *args):
-        await self.trigger_callbacks()
-
     @event_listener
     async def on_event_blockchain_updated(self, *args):
         await self.trigger_callbacks()