I'd presume that's present in the base game too, since I didn't chance the attack or battle.

6260545
Speedrunners use that trick all the time.

6260553
It lets you pass him?

6260556
No... It still treats it like you ran away.

You can also win this battle using Smoke Bombs with the same trick. And the only reason Smoke Ball works is because, running is an option. In other boss battles, running isn't an option, so Smoke Bombs don't work.