Also, mark feebumper bilingual_str as Untranslated
They are technical and have previously not been translated either.
It is questionable whether they can even appear in the GUI.
This is a partial backport of Cor PR18699 : https://github.com/bitcoin/bitcoin/pull/18699/commits/fae7776690c37104d2d4949429c5f84e6a33c576