Jax ml operator fix

[Ig-dolci]

Description

Depends on firedrakeproject/ufl#60

• Fixed an issue in firedrake.ml.jax.ml_operator where argument_slots was incorrectly specified. I wrote it as optional:

  argument_slots: Optional[tuple[Union[ufl.coefficient.BaseCoefficient, ufl.argument.BaseArgument]]] = ()

• Clarified that if argument_slots is not provided, ML_Operator will automatically write it.

• Test the results involving the Neural operators are in right function space.

• Test jax and pytorch operators in Firedrake CI.

[github-actions]

	Tests	Passed ✅	Skipped ⏭️	Failed ❌
Firedrake complex	8269 ran	6595 passed	1674 skipped	0 failed

[github-actions]

	Tests	Passed ✅	Skipped ⏭️	Failed ❌
Firedrake real	8198 ran	7500 passed	698 skipped	0 failed

[Ig-dolci]

@pbrubeck @dham Firedrake pip installs PR depends on the approval of UFL PR 348 and this PR.

[Ig-dolci]

The failure in the docs building is because of a recent Sphinx update.

[connorjward]

@pbrubeck if you are also happy it would be fantastic if this could be merged ASAP as it is holding up the pip PR. Naturally we need to update our UFL fork at the same time.