Correct slug handling by setting, not returning, values. #63584934

Per [bug 63584934](https://www.pivotaltracker.com/s/projects/593777/stories/63584934).  Previous fix in [PR 954](https://github.com/reciprocity/ggrc-core/pull/954) turned out not to work.  Problem was that `go_import` needs to set values when it was returning them without setting them.

Also, missed a fix from last time: title needs to be set as required per standard `Slugged` object convention.