Fix: Update cluster locations for map_reproducibility tests (GoogleCloudPlatform#751)

This commit updates the cluster names and regions for specific hardware configurations used in map_reproducibility tests.

The following changes were made in `dags/map_reproducibility/utils/common_utils.py`:
- For "a3ultra" hardware, the cluster is updated to "imo-a3ultra" in "europe-west1".
- For "a4" hardware, the cluster is updated to "gke-a4-sbrg1" in "us-east4".

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: bwuu

dags/map_reproducibility/utils/common_utils.py

@@ -1056,9 +1056,9 @@ def get_cluster(hardware: str = "a3ultra"):
   if hardware == "a3mega":
     return "a3plus-benchmark", "australia-southeast1"
   if hardware == "a3ultra":
-    return "gke-a3ultra-bm-map-3", "europe-west1"
+    return "imo-a3ultra", "europe-west1"
   if hardware == "a4":
-    return "gke-a4-shared", "us-central1"
+    return "gke-a4-sbrg1", "us-east4"
 
 
 def get_scheduled_time(hardware: str, model: str, framework: str):