Remove MPI wrappers for FMS and MAPL builds to enable apple-clang%15.x builds

[srherbener]

Summary

This PR is simply for syncing up the spack submodule hash for the spack PR (JCSDA/spack/pull/431) that enables builds of FMS and MAPL using apple-clang%15.x.

Testing

These changes were tested on my Mac using apple-clang%15.0.0 (Xcode 15.1).

Applications affected

FMS and MAPL are impacted. The usage of the MPI wrappers has been removed.

Systems affected

The MPI wrappers were removed unconditionally so these changes can affect the HPC platforms, plus MacOS, using FMS and MAPL.

Dependencies

• waiting on Remove use of MPI wrappers for fms and mapl package.py scripts spack#431

Issue(s) addressed

Fixes #1083

Checklist

• This PR addresses one issue/problem/enhancement, or has a very good reason for not doing so.
• These changes have been tested on the affected systems and applications. (Mac, several NOAA systems, see Enable MacOS, Sonoma (OS version 14.x) building of FMS and MAPL spack/spack#43726 for details)
• All dependency PRs/issues have been resolved and this PR can be merged.

[climbfuji]

Looks good. Will approve after the spack PR is merged etc.

[srherbener]

Ready for review. spack PR has been merged, and the spack submodule hash is updated here (and the .gitmodules file has been restored).