remove dumpgraph and inject_fees from cli

Those commands were only used for testing.

inject_fees was particularly misleading, because an electrum
instance with an active network connection regularly updates
its fees, thus voiding the effecct of that command.

electrum/commands.py

@@ -1199,16 +1199,6 @@ class Commands:
             } for channel_id, chan in backups
         ]
 
-    @command('wnl')
-    async def dumpgraph(self, wallet: Abstract_Wallet = None):
-        return wallet.lnworker.channel_db.to_dict()
-
-    @command('n')
-    async def inject_fees(self, fees):
-        # e.g. use from Qt console:  inject_fees("{25: 1009, 10: 15962, 5: 18183, 2: 23239}")
-        fee_est = ast.literal_eval(fees)
-        self.network.update_fee_estimates(fee_est=fee_est)
-
     @command('wnl')
     async def enable_htlc_settle(self, b: bool, wallet: Abstract_Wallet = None):
         wallet.lnworker.enable_htlc_settle = b