Fix dependencies on `orbit_assets` in tests (#286)

# Description

Fix dependencies on `orbit_assets` in some tests that use a policy which
is now included in the Isaac Nucleus server.

## Type of change

- Bug fix (non-breaking change which fixes an issue)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./orbit.sh --format`
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

source/extensions/omni.isaac.orbit/test/envs/check_base_env_anymal_locomotion.py

@@ -39,7 +39,6 @@ import torch
 import traceback
 
 import carb
-from omni.isaac.orbit_assets import ORBIT_ASSETS_DATA_DIR
 
 import omni.isaac.orbit.envs.mdp as mdp
 import omni.isaac.orbit.sim as sim_utils
@@ -54,7 +53,7 @@ from omni.isaac.orbit.scene import InteractiveSceneCfg
 from omni.isaac.orbit.sensors import RayCasterCfg, patterns
 from omni.isaac.orbit.terrains import TerrainImporterCfg
 from omni.isaac.orbit.utils import configclass
-from omni.isaac.orbit.utils.assets import check_file_path
+from omni.isaac.orbit.utils.assets import ISAAC_ORBIT_NUCLEUS_DIR, check_file_path
 from omni.isaac.orbit.utils.noise import AdditiveUniformNoiseCfg as Unoise
 
 ##
@@ -215,7 +214,7 @@ def main():
     obs, _ = env.reset()
 
     # load level policy
-    policy_path = os.path.join(ORBIT_ASSETS_DATA_DIR, "Policies", "ANYmal-C", "policy.pt")
+    policy_path = os.path.join(ISAAC_ORBIT_NUCLEUS_DIR, "Policies", "ANYmal-C", "policy.pt")
     # check if policy file exists
     if not check_file_path(policy_path):
         raise FileNotFoundError(f"Policy file '{policy_path}' does not exist.")

source/standalone/tutorials/04_envs/running_quadruped.py

@@ -39,7 +39,6 @@ import torch
 import traceback
 
 import carb
-from omni.isaac.orbit_assets import ORBIT_ASSETS_DATA_DIR
 
 import omni.isaac.orbit.envs.mdp as mdp
 import omni.isaac.orbit.sim as sim_utils
@@ -54,7 +53,7 @@ from omni.isaac.orbit.scene import InteractiveSceneCfg
 from omni.isaac.orbit.sensors import RayCasterCfg, patterns
 from omni.isaac.orbit.terrains import TerrainImporterCfg
 from omni.isaac.orbit.utils import configclass
-from omni.isaac.orbit.utils.assets import check_file_path
+from omni.isaac.orbit.utils.assets import ISAAC_ORBIT_NUCLEUS_DIR, check_file_path
 from omni.isaac.orbit.utils.noise import AdditiveUniformNoiseCfg as Unoise
 
 ##
@@ -217,7 +216,7 @@ def main():
     obs, _ = env.reset()
 
     # load level policy
-    policy_path = os.path.join(ORBIT_ASSETS_DATA_DIR, "Policies", "ANYmal-C", "policy.pt")
+    policy_path = os.path.join(ISAAC_ORBIT_NUCLEUS_DIR, "Policies", "ANYmal-C", "policy.pt")
     # check if policy file exists
     if not check_file_path(policy_path):
         raise FileNotFoundError(f"Policy file '{policy_path}' does not exist.")