Yarn upgrade causes some unit tests to fail

[zachmullen]

After yarn upgrade, the JobList had one test failure and the DataBrowser had several. I poked around at the job list failure and it was related to XHR mocking. Either our mocking wasn't adequately reset, or there's a genuine bug in the component that's causing more XHRs to be dispatched than we want. One thing I tried was downgrading vue-async-computed, but that was not the culprit.