fix(joint_state_broadcaster): suppress confusing warning for standard interfaces

When using standard interfaces like 'velocity' with the default mapping,
the warning 'Mapping from velocity to interface velocity will not be done'
is confusing because no mapping is actually needed.

This change only shows the warning when there's a custom mapping being
ignored (i.e., when interface name differs from the JointState field name).

Fixes #2261

Author: greencookie-afk

joint_state_broadcaster/src/joint_state_broadcaster.cpp

@@ -124,11 +124,16 @@ controller_interface::CallbackReturn JointStateBroadcaster::on_configure(
       params_.interfaces.end())
     {
       map_interface_to_joint_state_[interface] = interface;
-      RCLCPP_WARN(
-        get_node()->get_logger(),
-        "Mapping from '%s' to interface '%s' will not be done, because '%s' is defined "
-        "in 'interface' parameter.",
-        interface_to_map.c_str(), interface.c_str(), interface.c_str());
+      // Only warn if there's a custom mapping being ignored (interface != interface_to_map)
+      // When they're equal (e.g., both "velocity"), it's the standard case and no warning is needed
+      if (interface != interface_to_map)
+      {
+        RCLCPP_WARN(
+          get_node()->get_logger(),
+          "Mapping from '%s' to interface '%s' will not be done, because '%s' is defined "
+          "in 'interface' parameter.",
+          interface_to_map.c_str(), interface.c_str(), interface.c_str());
+      }
     }
     else
     {