Cannot create a HeightMap CollisionShape in Godot physics.

[madmiraal]

Godot version: 3.2.2 and master 93b50a6

OS/device including version:
Ubuntu 20.04

Issue description:
Cannot create a HeightMap CollisionShape in Godot physics. Trying to creating a HeightMap generates error:
Godot 4.0:

E 0:00:02:0073   set_data: Condition "!d.has("cell_size")" is true.
  <C++ Source>   servers/physics_3d/shape_3d_sw.cpp:1491 @ set_data()

Godot 3.2:

E 0:00:00.204   set_data: Condition "!d.has("cell_size")" is true.
  <C++ Source>  servers/physics/shape_sw.cpp:1640 @ set_data()

Steps to reproduce:
Use Godot physics, and either create a HeightMap in script or select it as the CollisionShape.

Minimal reproduction project:
Godot 4.0:
HeightMap-4.0.zip

Godot 3.2:
HeightMap-3.2.zip

[madmiraal]

Related to #32216.

[rburing]

The error no longer appears in Godot 3.5.1 or 4.0 RC 3.