Force hook standalone tests to single device

[lantiga]

What does this PR do?

A few failures in standalone tests are due to the fact that hook tests cannot be run on multiple devices (at least the way they are written), since prepare_data only runs on rank 0. This was the cause of rather obscure failures.

Since hook tests are verifying the sanity of the sequence of hooks, it's ok to limit to single device.

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📚 Documentation preview 📚: https://pytorch-lightning--20491.org.readthedocs.build/en/20491/

[github-actions]

⚡ Required checks status: All passing 🟢

Groups summary

🟢 pytorch_lightning: Tests workflow

Check ID	Status
pl-cpu (macOS-14, lightning, 3.9, 2.1, oldest)	success	✅
pl-cpu (macOS-14, lightning, 3.10, 2.1)	success	✅
pl-cpu (macOS-14, lightning, 3.11, 2.2.2)	success	✅
pl-cpu (macOS-14, lightning, 3.11, 2.3)	success	✅
pl-cpu (macOS-14, lightning, 3.12, 2.4.1)	success	✅
pl-cpu (macOS-14, lightning, 3.12, 2.5.1)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.9, 2.1, oldest)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.10, 2.1)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.11, 2.2.2)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.11, 2.3)	success	✅
pl-cpu (ubuntu-22.04, lightning, 3.12, 2.4.1)	success	✅
pl-cpu (ubuntu-22.04, lightning, 3.12, 2.5.1)	success	✅
pl-cpu (windows-2022, lightning, 3.9, 2.1, oldest)	success	✅
pl-cpu (windows-2022, lightning, 3.10, 2.1)	success	✅
pl-cpu (windows-2022, lightning, 3.11, 2.2.2)	success	✅
pl-cpu (windows-2022, lightning, 3.11, 2.3)	success	✅
pl-cpu (windows-2022, lightning, 3.12, 2.4.1)	success	✅
pl-cpu (windows-2022, lightning, 3.12, 2.5.1)	success	✅
pl-cpu (macOS-14, pytorch, 3.9, 2.1)	success	✅
pl-cpu (ubuntu-20.04, pytorch, 3.9, 2.1)	success	✅
pl-cpu (windows-2022, pytorch, 3.9, 2.1)	success	✅
pl-cpu (macOS-14, pytorch, 3.12, 2.5.1)	success	✅
pl-cpu (ubuntu-22.04, pytorch, 3.12, 2.5.1)	success	✅
pl-cpu (windows-2022, pytorch, 3.12, 2.5.1)	success	✅

These checks are required after the changes to tests/tests_pytorch/models/test_hooks.py.

🟢 pytorch_lightning: Azure GPU

Check ID	Status
pytorch-lightning (GPUs) (testing Lightning | latest)	success	✅
pytorch-lightning (GPUs) (testing PyTorch | latest)	success	✅

These checks are required after the changes to tests/tests_pytorch/models/test_hooks.py.

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Thank you for your contribution! 💜

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79%. Comparing base (9709c64) to head (5f6c325).
Report is 1 commits behind head on master.

❗ There is a different number of reports uploaded between BASE (9709c64) and HEAD (5f6c325). Click for more details.

HEAD has 102 uploads less than BASE

Flag	BASE (9709c64)	HEAD (5f6c325)
cpu	48	24
lightning	37	18
pytest	26	0
python3.9	12	6
lightning_fabric	7	0
python3.11	12	6
python3.10	6	3
gpu	2	0
python3.12	18	9

Additional details and impacted files

@@            Coverage Diff            @@
##           master   #20491     +/-   ##
=========================================
- Coverage      88%      79%     -9%     
=========================================
  Files         267      264      -3     
  Lines       23382    23327     -55     
=========================================
- Hits        20479    18364   -2115     
- Misses       2903     4963   +2060     

[Borda]

Does the fallback to single device defeat the purpose of the test?