### Godot version

v4.0 rc6

### System information

Windows 10

### Issue description

When using a ViewportTexture from a SubViewport on a TextureRect, it throws errors after running the scene once and then switching scenes in the editor.
![Pasted image 20230227212626](https://user-images.githubusercontent.com/44676282/221680047-984fa03e-33d1-4856-9a7f-1700b28423cf.png)


### Steps to reproduce

Run the canvas-scene once.
Switch to another scene in the editor.
Switch back to the canvas-scene

### Minimal reproduction project

[ViewportTextureError.zip](https://github.com/godotengine/godot/files/10844099/ViewportTextureError.zip)

GDCLASS(Viewport, Node);
public:
	enum Scaling3DMode {
		SCALING_3D_MODE_BILINEAR,
		SCALING_3D_MODE_FSR,
		SCALING_3D_MODE_MAX
	};
	enum PositionalShadowAtlasQuadrantSubdiv {
		SHADOW_ATLAS_QUADRANT_SUBDIV_DISABLED,
		SHADOW_ATLAS_QUADRANT_SUBDIV_1,
		SHADOW_ATLAS_QUADRANT_SUBDIV_4,
		SHADOW_ATLAS_QUADRANT_SUBDIV_16,
		SHADOW_ATLAS_QUADRANT_SUBDIV_64,
		SHADOW_ATLAS_QUADRANT_SUBDIV_256,
		SHADOW_ATLAS_QUADRANT_SUBDIV_1024,
		SHADOW_ATLAS_QUADRANT_SUBDIV_MAX,
	};
	enum MSAA {