Pinned torch==2.2.2 breaks CI due to numpy>=2.0

[edoaltamura]

What should we add?

The CI tests involving TorchConnector fail with

tgrad = tpredict.grad.detach().numpy()
RuntimeError: Numpy is not available

https://github.com/qiskit-community/qiskit-machine-learning/actions/runs/9753721897/job/26919448830#step:8:2473
because version 2.2.2 of PyTorch, pinned in #796, is no longer compatible with Numpy following the v. 2.0 release.

Proposed solution

Release the torch==2.2.2 constraint to install the latest Numpy 2.0-compatible version (>=2.3.1), keeping in mind the UTF-8 issue in PyTorch 2.3.0, #797 and pytorch/pytorch#124897, that was affecting the CI tests on Windows platform.