Adding another prefix to the existing list of unittest_import_strs

[psathyan]

Based on the test.id format found at id for those test module's throwing ImportError exceptions logic... the prefix for these tests would be unittest.loader._FailedTest

Snippet

(py311) [stack@osp-devstack-03 tempest]$ python -m stestr.subunit_runner.run discover -t "./" "./tempest/test_discover" --list

unittest.loader._FailedTest.cinder_tempest_plugin.api.volume.test_volume_revert

import errorsB�Failed to import test module: cinder_tempest_plugin.api.volume.test_volume_revert
Traceback (most recent call last):
  File "/usr/lib64/python3.11/unittest/loader.py", line 407, in _find_test_path
    module = self._get_module_from_name(name)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.11/unittest/loader.py", line 350, in _get_module_from_name
    __import__(name)
  File "/opt/stack/tempest/.tox/py311/lib/python3.11/site-packages/cinder_tempest_plugin/api/volume/test_volume_revert.py", line 19, in <module>
    from tempest.lib import exception
ImportError: cannot import name 'exception' from 'tempest.lib' (/opt/stack/tempest/tempest/lib/__init__.py)

Signed-off-by: Pragadeeswaran Sathyanarayanan [email protected]

[mtreinish]

LGTM