fix: update LocalCluster import path after cluster module reorganization

PR #3900 moved LocalCluster from iris.cluster.local_cluster to
iris.cluster.providers.local.cluster. Update the two test files that
still referenced the old path.

Author: rjpower

lib/iris/tests/test_auth.py

@@ -3,7 +3,7 @@
 """Auth tests for Iris controller with static token authentication."""
 
 import pytest
-from iris.cluster.local_cluster import LocalCluster
+from iris.cluster.providers.local.cluster import LocalCluster
 from iris.cluster.types import Entrypoint, ResourceSpec
 from iris.rpc import cluster_pb2
 from iris.rpc.cluster_connect import ControllerServiceClientSync

lib/iris/tests/test_checkpoint_restore.py

@@ -8,7 +8,7 @@
 
 from iris.client.client import IrisClient, Job
 from iris.cluster.config import load_config, make_local_config
-from iris.cluster.local_cluster import LocalCluster
+from iris.cluster.providers.local.cluster import LocalCluster
 from iris.cluster.types import Entrypoint, EnvironmentSpec, ResourceSpec, is_job_finished
 from iris.rpc import cluster_pb2
 from iris.rpc.cluster_connect import ControllerServiceClientSync