Phantom Camera disappears when re-adding a scene to a tree

[Paul-Griffin-1517-1]

Issue description

In my game, there is a PhantomCamera3D attached to the player and saved as a variable. At one point, the player is removed from the tree, but not freed. At a later point, the player is re-added to the tree.
At this point, the variable that referenced the PhantomCamera3D becomes null, and it becomes difficult to re-assign the variable PhantomCamera3D.
At the very least, it would be good to have an easy way to reassign the variable, since using the node's path (like in the @onready declaration) doesn't work at this point.

Steps to reproduce

Add a node with a PhantomCamera3D child.
In a script on the node, create an @onready variable called phantom_camera that equals the PhantomCamera3D.
Remove the node from the tree.
Re-add the node from the tree.
The phantom_camera variable will be empty.

(Optional) Minimal reproduction project

No response