message: param: corrected async func for get_param_float()
diff: @@ -342,7 +342,7 @@ MAVLinkParameters::get_param_float(const std::string& name, bool extended)
  auto prom = std::promise<std::pair<Result, float>>();
  auto res = prom.get_future();
  - get_param_int_async(
  + get_param_float_async(
  name,
  [&prom](Result result, float value) { prom.set_value(std::make_pair<>(result, value)); },
  this,
  