remove naming artifact

Author: ooctipus

source/isaaclab/isaaclab/sim/spawners/wrappers/wrappers.py

@@ -57,7 +57,7 @@ def spawn_multi_asset(
             if hasattr(asset_cfg, attr_name) and attr_value is not None:
                 setattr(asset_cfg, attr_name, attr_value)
         # spawn single instance
-        proto_prim_path = prim_path.replace(".*", f"{index:04d}")
+        proto_prim_path = prim_path.replace(".*", f"{index}")
         asset_cfg.func(
             proto_prim_path,
             asset_cfg,