tripleoclient: unit tests are failing because of missing glanceclient

Description
===========
Currently unit tests of python-tripleoclient are consistently failing, due to missing glanceclient.

example:
https://zuul.opendev.org/t/openstack/build/42f40bbfb0104025947012c0eee7f570
https://storage.bhs.cloud.ovh.net/v1/AUTH_dcaab5e32b234d56b626f72581e3644c/zuul_opendev_logs_42f/862972/6/check/openstack-tox-py38/42f40bb/job-output.txt

2022-11-08 08:37:22.716387 | ubuntu-focal | Failed to import test module: tripleoclient.tests.v1.overcloud_image.test_overcloud_image
2022-11-08 08:37:22.716403 | ubuntu-focal | Traceback (most recent call last):
2022-11-08 08:37:22.716415 | ubuntu-focal | File "/usr/lib/python3.8/unittest/loader.py", line 436, in _find_test_path
2022-11-08 08:37:22.716426 | ubuntu-focal | module = self._get_module_from_name(name)
2022-11-08 08:37:22.716437 | ubuntu-focal | File "/usr/lib/python3.8/unittest/loader.py", line 377, in _get_module_from_name
2022-11-08 08:37:22.716447 | ubuntu-focal | __import__(name)
2022-11-08 08:37:22.716458 | ubuntu-focal | File "/home/zuul/src/opendev.org/openstack/python-tripleoclient/tripleoclient/tests/v1/overcloud_image/test_overcloud_image.py", line 26, in <module>
2022-11-08 08:37:22.716469 | ubuntu-focal | from tripleoclient.v1 import overcloud_image
2022-11-08 08:37:22.716479 | ubuntu-focal | File "/home/zuul/src/opendev.org/openstack/python-tripleoclient/tripleoclient/v1/overcloud_image.py", line 25, in <module>
2022-11-08 08:37:22.716490 | ubuntu-focal | from glanceclient.common.progressbar import VerboseFileWrapper
2022-11-08 08:37:22.716500 | ubuntu-focal | ModuleNotFoundError: No module named 'glanceclient'
2022-11-08 08:37:22.716513 | ubuntu-focal |

The current tripleoclient requires glanceclient and the library was indirectly required by tripleo-common but we removed that dependency a while ago by [1].