Parts of translations don't work in Unlock Veracrypt Volumes

Originally created by @xin on #16602 (Redmine)

In Tails in French, the text is in English in the Unlock Veracrypt Volumes.
Except fields with “No file containers added” and “No VeraCrypt devices detected” which are in French.
All this content is translated in po/fr.po. This bug may be present since 3.9 release.

Feature Branch: bugfix/16602-parts-of-unlock-veracrypt-volumes-not-translated

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