fix(object_velocity_splitter): delete default param in src (autowarefoundation#6313)

Signed-off-by: scepter914 <scepter914@gmail.com>

Author: scepter914

perception/object_velocity_splitter/src/object_velocity_splitter_node/object_velocity_splitter_node.cpp

@@ -53,7 +53,7 @@ ObjectVelocitySplitterNode::ObjectVelocitySplitterNode(const rclcpp::NodeOptions
     std::bind(&ObjectVelocitySplitterNode::onSetParam, this, std::placeholders::_1));
 
   // Node Parameter
-  node_param_.velocity_threshold = declare_parameter<double>("velocity_threshold", 3.0);
+  node_param_.velocity_threshold = declare_parameter<double>("velocity_threshold");
 
   // Subscriber
   sub_objects_ = create_subscription<DetectedObjects>(