Remove workaround for intel oneAPI in `palace-ci`

[Sbozzolo]

#578 introduces a workaround for intel compilers and spack.

Spack 1.2.0-alpha and oneAPI-2025.3.1 have some compatibility problems where the version of the fortran compiler is not correctly identified. As a workaround, we add a step in the palace-ci action where we manually edit the relevant entry in the spack.yaml to put all the compilers under the same version.

This should not be needed and it will be hopefully fixed in future versions of spack/oneAPI. We should periodically check if this is fixed and remove the relevant entry from the action.