I'd love to help, but I'm not sure I understand. Which messages do you want to change? You are not supposed to need an interface administrator permission to transate here.
This doesn't look like a message that is supposed to require the editinterface permission. I strongly suspect that this is a bug in core MediaWiki or in the Translate extension. I reported it in Phabricator: https://phabricator.wikimedia.org/T222034
Thanks for pinging me about this. I hope that this will be fixed soon.
I think so. The problem is still not fixed. I get the following message: "Permissions for editing of sitewide CSS/JS/JSON files were recently separated from the editinterface right. If you do not understand why you are getting this error, see mw:MediaWiki_1.32/interface-admin."