Improve link-checker and fix Tracer issue

[kcelia]

In this PR:

• I removed the issues 4563 and 4579, spotted by the bot and also discussed in slack
• I refactored tests/torch/test_compile_torch.py::test_qat_import_check test to improve clarity and isolate Tracer._is_tracing
• I moved AllZeroCNN to the torch_models file
• Skip Temporarily: CNNOther (see issue)

closes https://github.com/zama-ai/concrete-ml-internal/issues/4667

[github-actions]

⚠️ Known flaky tests have been rerun ⚠️

One or several tests initially failed but were identified as known flaky. tests. Therefore, they have been rerun and passed. See below for more details.

Failed tests details

Known flaky tests that initially failed:

• tests/torch/test_compile_torch.py::test_compile_torch_or_onnx_conv_networks[False-True-CNN_conv1d-relu]

[github-actions]

Coverage passed ✅

Coverage details

---------- coverage: platform linux, python 3.8.18-final-0 -----------
Name    Stmts   Miss  Cover   Missing
-------------------------------------
TOTAL    8414      0   100%

62 files skipped due to complete coverage.

[andrei-stoian-zama]

Excellent, thanks!