usb-acl-helper shouldn't need CAP_FOWNER
Related to the changes done in !42 (closed), I think the usb-acl-helper should be redesigned.
It shouldn't need to change the USB devices ACL. Instead, it could have the minimum privileges to open it and pass it to the client. libusb has support for this with
libusb_wrap_sys_device() since 2019-08-28: v1.0.23.
I would rely on dbus & systemd to do that.