Add-on store: pluralize one string (#19059)
Fix-up of #18974
Summary of the issue:
One newly translatable string needs to support plural forms:
"{malicious} out of {total} malware scanners detected this add-on as potentially malicious."
In English, there is no difference, since "detected" uses the same form at singular or plural; but in other languages, not. There are also languages where scanners pluralization needs to change.
Description of user facing changes:
The information will have correct pluralization form.
After discussion, I have tried to find a wording where only one of the two numbers needs an agreement to avoid splitting and re-building the sentence.
Description of developer facing changes:
N/A
Description of development approach:
Use npgettext instead of pgettext.
