Rename CFD-DEM tests that have restarts to start with "restart_"

[blaisb]

Description

While refactoring the DEM, @OGaboriault and I realized that the tests that have restart components are weirdly named. Some start with restart_, some end with _restart, and so on and so forth. This is a first step to uniformize the name of the tests that include restarts for CFD-DEM

Testing

Only the test names have been changed, nothing has changed regarding the results or the restart files themselves.

Documentation

Nothing changed here.

Miscellaneous (will be removed when merged)

Checklist (will be removed when merged)

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Code related list:

• All in-code documentation related to this PR is up to date (Doxygen format)
• Copyright headers are present and up to date
• Lethe documentation is up to date
• The branch is rebased onto master
• Code is indented with indent-all and .prm files (examples and tests) with prm-indent
• If parameters are modified, the tests and the documentation of examples are up to date
• Changelog (CHANGELOG.md) is up to date if the refactor affects the user experience or the codebase

Pull request related list:

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• The PR description is cleaned and ready for merge