Update reading output files in FHI-aims SocketIO workflow

[ansobolev]

Summary

This PR updates how atomate2 reads FHI-aims output files for SocketIO calculation flows to be compatible with pyfhiaims ≥ 1.0.

In version 1.0, pyfhiaims.external_interfaces was removed in favor of plugin-based integrations with packages like ASE and pymatgen. Previously, atomate2 used pymatgen.io.aims.outputs.AimsOutput in most cases, but relied on ASE via the pyfhiaims external interface for SocketIO workflows.

This PR removes that inconsistency by switching SocketIO output parsing to also use pymatgen.io.aims.outputs.AimsOutput, aligning it with the rest of the codebase.

See PR #1461 for related CI failures caused by the removal of the external interface.

@tpurcell90, can you check if all is good here?

• Fix using ASE external interface for SocketIO in favor of pymatgen.io.aims

Checklist

Before a pull request can be merged, the following items must be checked:

• Code is in the standard Python style.
  The easiest way to handle this is to run the following in the correct sequence on
  your local machine. Start with running ruff and ruff format on your new code. This will
  automatically reformat your code to PEP8 conventions and fix many linting issues.
• Doc strings have been added in the Numpy docstring format.
  Run ruff on your code.
• Type annotations are highly encouraged. Run mypy to
  type check your code.
• Tests have been added for any new functionality or bug fixes.
• All linting and tests pass.

Note that the CI system will run all the above checks. But it will be much more
efficient if you already fix most errors prior to submitting the PR. It is highly
recommended that you use the pre-commit hook provided in the repository. Simply run
pre-commit install and a check will be run prior to allowing commits.

[tpurcell90]

I'm trying to debug/check the socket calcs now

[esoteric-ephemera]

Thanks @ansobolev and @tpurcell90! Let me know when this is ready and I can merge it