Add python wrapper for FiniteElement.basix_element

[schnellerhase]

Switches to use the Basix python type for the returned element.

Ping #3553

[schnellerhase]

oneAPI CI also fails on main - not caused by this PR.

[garth-wells]

A concern/issue in the past has been how tightly we couple Basix Python objects and DOLFINx Python objetcs

[jorgensd]

A concern/issue in the past has been how tightly we couple Basix Python objects and DOLFINx Python objetcs

We need to expose the basix element in some way (being wrapped as a basix python or c++ object), as we do not interface to all the functionality of the C++ element through dolfinx::fem::FiniteElement.

As of now, there is not really any other alternative than using a basix element within DOLFINx.

[garth-wells]

A concern/issue in the past has been how tightly we couple Basix Python objects and DOLFINx Python objetcs

We need to expose the basix element in some way (being wrapped as a basix python or c++ object), as we do not interface to all the functionality of the C++ element through dolfinx::fem::FiniteElement.

As of now, there is not really any other alternative than using a basix element within DOLFINx.

The required functionality can be wrapped.

The change will force Basix and DOLFINx to use nanobind, and to use precisely the same nanobind version. Small changes were made previously when DOLFINx used nanobind and Basix still used pybind11 to allow this. It's good to avoid unnecessarily tight coupling.

One of the reasons we wrap Basix elements on the DOLFINx side is to keep open the possibility of having a DOLFINx element that isn't backed by a Basix element.