Remove .get calls for dry_run - it's a mandatory property

freqtrade/rpc/rpc_manager.py

@@ -62,7 +62,7 @@ class RPCManager:
                 logger.error(f"Message type {msg['type']} not implemented by handler {mod.name}.")
 
     def startup_messages(self, config, pairlist) -> None:
-        if config.get('dry_run', False):
+        if config['dry_run']:
             self.send_msg({
                 'type': RPCMessageType.WARNING_NOTIFICATION,
                 'status': 'Dry run is enabled. All trades are simulated.'