Is the English-version of a paper previously published in a different language considered an "original contribution"?
No.  A translation is not considered an original work in the context of submission to an academic journal whose stated policy is that submissions must be original work that is not published elsewhere.*
You can still send an email to the editor explaining your idea and asking if they’d make an exception to the policy. Some journals, in some circumstances, might consider it.
You can also translate your paper anyway and make the translation available via a paper repository such as arXiv. It will undoubtedly increase the exposure and impact of your work.
*Translation is of course a creative activity requiring skill and expertise, and in other contexts would certainly be considered a kind of original work.