Replace np.trapz with np.trapezoid for area calculation

[jacobrgardner]

For #2695

[jacobrgardner]

Unit tests need an environment update too I guess: https://numpy.org/doc/2.4/reference/generated/numpy.trapezoid.html

[jacobrgardner]

Hmm okay, we'd also need to bump the pytorch min version to 2.2 per this comment:

gpytorch/.github/workflows/run_test_suite.yml

Line 53 in c019c6d

pip install "numpy<2" # Numpy 2.0 is not fully supported until PyTorch 2.2

@Balandat botorch's pyproject currently only requires 2.0.1, so y'all are kind of in this blast radius of this one line change potentially. Thoughts about this?

[Balandat]

@jacobrgardner torch 2.2 is two years old by now, I think it's fine to bump the requirement up to 2.2 we can do the same thing on the botorch side. That will help simplify some of our CI logic so that's a side benefit. cc @saitcakmak

[Balandat]

Superseded by #2721