Test without void fraction bounding

[blaisb]

Description

As part of the current void fraction refactoring I wish to aim at deprecating the void fraction bounding after the refactoring is done. This requires modifying the test that currently use void fraction bounds. This PR updates the tests that use lethe-fluid-vans to not bound the void fraction. This is all it does, update the tests.

Testing

Test results are updated.

Documentation

Nothing to be done 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:

• No other PR is open related to this refactoring
• Labels are applied
• There are at least 2 reviewers (or 1 if small feature) excluding the responsible for the merge
• If this PR closes an issue or is related to a project, it is linked in the "Projects" or "Development" section
• If any future works is planned, an issue is opened
• The PR description is cleaned and ready for merge