Listing blobs is not wrapped in a re-try

[rzvoncek]

Project board link

Observed the following exception in the wild:

Traceback (most recent call last):
  File "/home/cassandra/medusa/backup_node.py", line 280, in backup_snapshots
    files_in_storage = storage.list_files_per_table()
  File "/home/cassandra/medusa/storage/__init__.py", line 496, in list_files_per_table
    all_blobs: t.List[AbstractBlob] = self.storage_driver.list_blobs(prefix=fdns_data_prefix)
  File "/home/cassandra/medusa/storage/abstract_storage.py", line 80, in list_blobs
    objects = loop.run_until_complete(self._list_blobs(prefix))
  File "/usr/lib/python3.10/asyncio/base_events.py", line 649, in run_until_complete

This happened because we don't annotate the [list_blobs] with a retry for some reason.

We need to add the retry to protect ourselves from the exception.