I'll answer for the use of translation because i'm not sure what happens with
move (need to test that, could be a bug with that method).
set_translation won't toggle the colliding flag, it will need the help of another node...
You can add a couple of raycasts below the door, the amount, length and location of the rays will depend on the door movement, speed and the shapes of bodies to intercept, iterate the rays for their is_colliding.
Another option is to add an area below the door (a small one or all the frame) and check
get_overlapping_bodies (for the size and type/group of the bodies) or the signal
body_enter to stop the door and/or make it open.
And... you can make the bodies that touch the door tell the door they are below, but it will depend much on the design because the character may be touching stuff all the time and that check may turn a bit inefficient.