Fix suggestOne/ManyDirectory language fallback when user locale not available

When trying to get suggestions from a directory where tranlations are in the column of the directory, if the user locale is not availale in the directory, then displayed labels are empty. This the case for widgets using l10ncoverage, l10nsubjets directories.

To reproduce:

• Change the locale of the current user (let's say vietnamese)
• Edit a document which has coverage
• Try change the coverage.