DPL-761 [BUG] PlatePurpose::AdditionalInput is not unit tested

[emrojo]

Describe the bug The class PlatePurpose::AdditionalInput does not have tests because of problems on setting up the environment. We currently don't have slack of time to spend in the issue. The higher level functionality provided is tested in an integration suite however this is far from ideal, we would like to find a way of running tests for this class and understand what was the issue.

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