[MAPLE-681] Add robot_description_package as parameter to driver laun…

…ch (#531)

## Change Overview
This allows you to change the pack from where to get the robot description. This allows us to have different configurations of the robot (such as custom payloads)
Makes the (hard) assumption that whatever package you point it to has `{package}/urdf/spot.urdf.xacro` in it.

@tcappellari-bdai @khughes-bdai feel free to agree/disagree with this, but only way I could get extra collision objects in as needed on hardware

spot_driver/launch/spot_driver.launch.py

@@ -23,6 +23,7 @@ def launch_setup(context: LaunchContext, ld: LaunchDescription) -> None:
     spot_name = LaunchConfiguration("spot_name").perform(context)
     tf_prefix = LaunchConfiguration("tf_prefix").perform(context)
     mock_enable = IfCondition(LaunchConfiguration("mock_enable", default="False")).evaluate(context)
+    robot_description_package = LaunchConfiguration("robot_description_package").perform(context)
 
     # if config_file has been set (and is not the default empty string) and is also not a file, do not launch anything.
     config_file_path = config_file.perform(context)
@@ -35,7 +36,7 @@ def launch_setup(context: LaunchContext, ld: LaunchDescription) -> None:
     else:
         has_arm = spot_has_arm(config_file_path=config_file.perform(context), spot_name=spot_name)
 
-    pkg_share = FindPackageShare("spot_description").find("spot_description")
+    robot_description_pkg_share = FindPackageShare(robot_description_package).find(robot_description_package)
 
     # Since spot_image_publisher_node is responsible for retrieving and publishing images, disable all image publishing
     # in spot_driver.
@@ -85,7 +86,7 @@ def launch_setup(context: LaunchContext, ld: LaunchDescription) -> None:
         [
             PathJoinSubstitution([FindExecutable(name="xacro")]),
             " ",
-            PathJoinSubstitution([pkg_share, "urdf", "spot.urdf.xacro"]),
+            PathJoinSubstitution([robot_description_pkg_share, "urdf", "spot.urdf.xacro"]),
             " ",
             "arm:=",
             TextSubstitution(text=str(has_arm).lower()),
@@ -184,6 +185,13 @@ def generate_launch_description() -> launch.LaunchDescription:
             description="Choose whether to launch the image publishing nodes from Spot.",
         )
     )
+    launch_args.append(
+        DeclareLaunchArgument(
+            "robot_description_package",
+            default_value="spot_description",
+            description="Package from where the robot model description is. Must have path /urdf/spot.urdf.xacro",
+        )
+    )
     launch_args += declare_image_publisher_args()
     launch_args.append(DeclareLaunchArgument("spot_name", default_value="", description="Name of Spot"))