Update file names to copy for snapshotRequest

[mgjarrett]

Description

The snapshotInterface needed an interactCoupled method. Also, the file names for latticePhysics and neutronics kernel files to be copied needed to be updated.

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Checklist

• This PR has only one purpose or idea.
• Tests have been added/updated to verify that the new/changed code works.

• The code style follows good practices.
• The commit message(s) follow good practices.

• The release notes (location doc/release/0.X.rst) are up-to-date with any important changes.
• The documentation is still up-to-date in the doc folder.
• The dependencies are still up-to-date in setup.py.

[john-science]

I hope to see more use of unittest.mock in ARMI!

And I'm surprised to see this is our first use of mock.patch in ARMI!