fix: workloads not scheduling on A3 Ultra clusters (#441)

Author: gcie

src/xpk/core/workload_decorators/rdma_decorator.py

@@ -85,7 +85,7 @@ def add_annotations(job_manifest: dict, sub_networks: list[str]):
   annotations = job_manifest['spec']['template']['metadata']['annotations']
   interfaces_key, interfaces_value = get_interfaces_entry(sub_networks)
   annotations.update({
-      'networking.gke.io/default-interface': "'eth0'",
+      'networking.gke.io/default-interface': 'eth0',
       interfaces_key: interfaces_value,
   })