Fix vault delete print line

Author: libutcher

example/example.py

@@ -249,7 +249,7 @@ async def showcase_vault_operations(client: Client):
     # [developer-docs.sdk.python.delete-vault]-start
     # Delete a vault
     await client.vaults.delete(created_vault.id)
-    print(f"Vault {vault_id} successfully deleted.")
+    print(f"Vault {created_vault.id} successfully deleted.")
     # [developer-docs.sdk.python.delete-vault]-end
 
     # [developer-docs.sdk.python.list-vault]-start