[subplat][l10n] Invoice Intervals are Difficult to Localize

[data-sync-user]

From Peiying Mo via Slack:

{quote}【 highlighted #1d1c1d 】This issue was brought up a few times by the communities, on the intervals of invoicing. They need more context in the comment for the specific strings (but may not be doable if the file is not in Fluent). The structure the variables is challenging for some languages, so let's see how we can make it better. One of the examples 【 end highlighted 】https://pontoon.mozilla.org/it/firefox-accounts/all-resources/?status=missing&string=224251【 highlighted #1d1c1d 】was mentioned in 【 end highlighted 】#8705
{quote}

┆Issue is synchronized with this Jira Task
┆Issue Number: FXA-3645