Follow-up changes to spack and spack-packages updates from upstream

[climbfuji]

Description

Pull requests #2025 and TO BE CREATED update spack and spack-packages from upstream (spack develop).

There are new warnings about legacy compiler requirements that we should address in a follow-up PR:

[ue-oneapi-2026.0.0] [dom@bounty spack-stack-upd-spack-packages]$ spack concretize --force --fresh 2>&1 | tee log.concretize.ue-oneapi-2026.0.0
==> Warning: /home/dom/work/spack-stack/spack-stack-upd-spack-packages/envs/ue-oneapi-2026.0.0/site/packages.yaml:6: 'packages: all: require: ["%intel-oneapi-compilers@=2026.0.0"]' applies a dependency constraint to all packages. This often leads to concretization errors. This was likely intended as a requirement for a provider of a (language) virtual. Consider instead:
# For each language virtual (c, cxx, fortran, ...):
packages:
  c:
    require:
    - intel-oneapi-compilers@=2026.0.0
==> Warning: /home/dom/work/spack-stack/spack-stack-upd-spack-packages/envs/ue-oneapi-2026.0.0/site/packages.yaml:8: 'packages: all: require: ["%gcc@=11.5.0"]' applies a dependency constraint to all packages. This often leads to concretization errors. This was likely intended as a requirement for a provider of a (language) virtual. Consider instead:
# For each language virtual (c, cxx, fortran, ...):
packages:
  c:
    require:
    - gcc@=11.5.0