You need to save the “state” of the door.
You also might to check if the other animation is still playing.
#[...]
var is_open : bool = false
func _process(_delta : float) -> void:
if Input.is_action_just_pressed("Interact"):
if bodyNearDoor and not animationDoor.is_playing():
if not is_open:
animationDoor.play("Door_Open")
is_open = true
else:
animationDoor.Play("Door_Close")
is_open = false
#[...]
The part that you indicated as not working is using wrong built-in function.
It should be :
if animationdoor.is-playing() == true and animationdoor.current-animation == “Door Open”