The easiest way is to create a treble clef as a custom playing technique. Then in the Music Symbols editor, find the treble clef and delete it. Then add the treble clef to the first staff as a “playing technique.”
I say that’s the easiest way, but it’s the only way I know! It feels janky but works pretty well.
There is an “invisible treble clef” in the Uncommon Clefs tab in the right hand side panel. Just put a clef change after the first note.
But there isn’t an invisible bass clef, so if you want that you will have to do something like Dan’s work round.