message: backend: remove assert because it would trigger
  We need to remove this assert because we now initialize the GRPC server
  without having a vehicle connected and therefore, the system list of
  system UUIDs can be empty. This doesn't matter because the default/dummy
  system is still valid and the plugins will be ok later.
diff: @@ -30,10 +30,7 @@ public:
  _mission(_dc.system()),
  _mission_service(_mission),
  _telemetry(_dc.system()),
  - _telemetry_service(_telemetry)
  - {
  - assert(_dc.system_uuids().size() >= 1);
  - }
  + _telemetry_service(_telemetry) {}
  void run();
  void wait();
  