Fixes for compatibility with firedrake release 2025.4.1

[JHopeCollins]

This fixes errors and warnings so asQ works with the latest firedrake release.
Once this is merged we can make a tagged asQ release so we're then free to develop on asQ/master using firedrake/master.

1. Update the github workflow for the pip install and release changes.
2. Fix for petsc changing default return val for an empty prefix.
3. Warning fix for FunctionSpace.subfunctions -> subspaces.
4. Warning fix for passing quadrature_degree to project.

[JHopeCollins]

There is one test that is failing by hanging and timing out (the Nitsche time-dependent bcs test), but I can't replicate it locally. This isn't new, we think it's related to the ensemble compiling the same form simultaneously on different members, but have never found the root cause for certain, or a reliable fix yet.

For now I think we should merge this as the failure is unrelated to the updates, and is rarely seen locally.

[colinjcotter]

good to go.
Let's keep an eye on that timing out test though.