Planechase: add missing SBA

> 704.6f. In a Planechase game, if a phenomenon card is face up in the command zone, and it isn't the source of a triggered ability that has triggered but not yet left the stack, the planar controller planeswalks. See rule 901, "Planechase."

It matters if something would mess with the trigger like copying or even countering (then the card might be stuck?)

`DB$ Planeswalk` should then be removed from scripts.