Dealing TimeoutExceptions when extracting accounts from Sign

[Luci2015]

Description
If TimeoutException is raised during Sign sync, this is the error may be obtained:

"2023-11-21 11:32:39 6616 ERROR asyncio - Task exception was never retrieved
future: <Task finished name='Task-442' coro=<SignClient._get_user() done, defined at sign_client\client.py:261> exception=TypeError('super(type, obj): obj must be an instance or subtype of type')>
Traceback (most recent call last):
  File "sign_client\client.py", line 266, in _get_user
  File "sign_client\client.py", line 336, in call_with_retry_async
  File "sign_client\error.py", line 36, in __init__
TypeError: super(type, obj): obj must be an instance or subtype of type
2023-11-21 11:32:39 6616 ERROR asyncio - Task exception was never retrieved
future: <Task finished name='Task-443' coro=<SignClient._get_user() done, defined at sign_client\client.py:261> exception=TypeError('super(type, obj): obj must be an instance or subtype of type')>

Steps to reproduce
-> in the wild, it has to be raised by a >=500 or 429 error received from Sign API, but locally the error.py in sign_client can be used for testing and force a raise of TimeoutException

• Relevant config options
  set up the run for a usual Sign sync with no cache

Expected behavior
retry should happen for failed attempts, based on the described except branch

Environment

• UST version: > 2.6.0
• OS type and version: all