Apparently the eval trick doesn't work for passing vars if the var to set is the same as the var for the value, in this case the caller of this function was using `added_paths` and `removed_paths`. Shell scripts suck. This was missed in the tests because the unit tests call trigger_unit_presets directly. Part-of: <https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/7025>