Make linked_portal_door StartActive "yes" by default

[hexaflexahexagon]

I don't know if p2ce likes it better this way with how maps use portals, if so consider game-locking this

Suggested by touny

[vrad-exe]

It would probably be good to switch this based on game, in Portal you often have worldportals behind doors where you don't want them to open until the door itself opens.

[tmob03]

Can be closed ^^