[cloud] re-raise boto ClientError if throttling timeout is reached in efs.py (#23109)

* re-raise exception as expected

The current ThrottlingException handling code hides other actual exceptions from the user, and basically goes infinite loop instead. eg when the api caller doesn't have permission (example below) to use the api, ansible effectively hangs. adding the re-raise stops execution and shows the error to the command line as expected

can test by removing permission to the efs api, and calling the efs: module

The error was: botocore.exceptions.ClientError: An error occurred (AccessDeniedException) when calling the DescribeFileSystems operation: User: <x> is not authorized to perform: elasticfilesystem:DescribeFileSystems on the specified resource

* PEP8 fix

lib/ansible/modules/cloud/amazon/efs.py

@@ -516,6 +516,9 @@ def iterate_all(attr, map_method, **kwargs):
                 sleep(wait)
                 wait = wait * 2
                 continue
+            else:
+                raise
+
 
 def targets_equal(keys, a, b):
     """