pytest 8 has issues with `pytest.warns`

Some of our tests that use pytest.warns started failing with pytest 8 which was released a few days ago.
I'm just opening this issue for reference and to add as a TODO.

https://github.com/pytorch/vision/actions/runs/7694476421/job/20965356912?pr=7990

2024-01-29T10:34:47.7500403Z FAILED test/test_extended_models.py::TestHandleLegacyInterface::test_pretrained_pos[True] - UserWarning: Arguments other than a weight enum or `None` for 'weights' are deprecated since 0.13 and may be removed in the future. The current behavior is equivalent to passing `weights=ModelWeights.Sentinel`. You can also use `weights=ModelWeights.DEFAULT` to get the most up-to-date weights.
2024-01-29T10:34:47.7505456Z FAILED test/test_extended_models.py::TestHandleLegacyInterface::test_pretrained_pos[False] - UserWarning: Arguments other than a weight enum or `None` for 'weights' are deprecated since 0.13 and may be removed in the future. The current behavior is equivalent to passing `weights=None`.
2024-01-29T10:34:47.7508764Z FAILED test/test_extended_models.py::TestHandleLegacyInterface::test_equivalent_behavior_weights[True-True] - UserWarning: Using 'weights' as positional parameter(s) is deprecated since 0.13 and may be removed in the future. Please use keyword parameter(s) instead.
2024-01-29T10:34:47.7511905Z FAILED test/test_extended_models.py::TestHandleLegacyInterface::test_equivalent_behavior_weights[True-False] - UserWarning: Using 'weights' as positional parameter(s) is deprecated since 0.13 and may be removed in the future. Please use keyword parameter(s) instead.
2024-01-29T10:34:47.7514909Z FAILED test/test_extended_models.py::TestHandleLegacyInterface::test_equivalent_behavior_weights[False-True] - UserWarning: The parameter 'pretrained' is deprecated since 0.13 and may be removed in the future, please use 'weights' instead.
2024-01-29T10:34:47.7517759Z FAILED test/test_extended_models.py::TestHandleLegacyInterface::test_equivalent_behavior_weights[False-False] - UserWarning: The parameter 'pretrained' is deprecated since 0.13 and may be removed in the future, please use 'weights' instead.
2024-01-29T10:34:47.7521326Z FAILED test/test_extended_models.py::TestHandleLegacyInterface::test_pretrained_deprecation[inception_v3_1] - FutureWarning: The default weight initialization of inception_v3 will be changed in future releases of torchvision. If you wish to keep the old behavior (which leads to long initialization times due to scipy/scipy#11299), please set init_weights=True.

Start with test/test_extended_models.py and the listed TestHandleLegacyInterface cases, running them with pytest 8 to inspect the changed pytest.warns behavior. Determine the test updates needed for the reported warnings, then confirm all affected cases pass under pytest 8.