chore: Replace `TestCase` with `pytest` test suite or test case

[viniarck]

chore: Replace TestCase with pytest test suite or test case

❯ rg TestCase -g "*.py"
tests/unit/managers/test_deployer.py
3:from unittest import TestCase
19:class TestDeployer(TestCase):

tests/unit/managers/test_scheduler.py
3:from unittest import TestCase
19:class TestScheduler(TestCase):

tests/unit/test_models.py
3:from unittest import TestCase
13:class TestMW(TestCase):

tests/unit/test_controller.py
3:from unittest import TestCase
12:class TestMaintenanceController(TestCase):

@Ktmi this is low priority, but if you could add to your radar just so it can be addressed in a next opportunity, that'd be great.