OOB migration admin page re-renders components each update

Created by: LawnGnome

This manifests most annoyingly as the expanded state of the error Collapsible being reset every few seconds, which makes it a little challenging to actually read the errors.

I am fluent enough in React to know that it's because this callback is being recomputed each render. I am not fluent enough in RxJS to figure out why the observable it depends upon is changing.

Assigning to self, mostly so I remember to grab a teammate who is fluent in RxJS to help me understand this.