Tbh, I don't know if they died. That armor is pretty good, and they could survive.Stuff from Star Wars have been far and between. I think this season only saw a small handful of Mandalorian warrior fall in battle including one female getting blasted a couple weeks ago.
I would be sure if they were stormtroopers, and I think that captain chick from Ahsoka trailer is certainly going to die. But we have to wait few months to see that scene.