Angular vandelay: it's easy to lose your work in the Record Match Set editor

In current master

Steps to reproduce:
* Go to [hostname]/eg2/en-US/staff/cat/vandelay/match_sets
* Create a new match set, if you don't already have one.
* Click on the name of your match set.
* Craft a really awesome, lovely match set with a bunch of boolean operators, MARC tags/subfields, and Record Attributes.
* Click on the Match Set Quality Metrics tab. Or another top-level tab within the Vandelay Angular interface. Or a different Evergreen screen.
* Go back to the editor for your match set. Note that all your hard work is gone.