fix Tiltfile

Co-authored-by: Nawaz K <[email protected]>

Author: rihib

Tiltfile

@@ -50,7 +50,7 @@ if "allowed_contexts" in settings:
 if "default_registry" in settings:
     default_registry(settings.get("default_registry"))
 
-mgmt_cluster_type = os.getenv("MGMT_CLUSTER_TYPE")
+mgmt_cluster_type = os.getenv("MGMT_CLUSTER_TYPE", "")
 os_arch = str(local("go env GOARCH")).rstrip("\n")
 if mgmt_cluster_type == "aks":
     print("Using AKS as management cluster, setting os_arch to amd64")