Textures specified in an OmniLight3D or SpotLight3D projector are not detected as used in 3D

[Calinou]

Related to #62031.

Godot version

4.0.alpha (1847094)

System information

Fedora 36, GeForce GTX 1080 (NVIDIA 510.68.02)

Issue description

Unlike textures specified in a BaseMaterial3D, textures specified in an OmniLight3D or SpotLight3D's Projector property are not detected as used in 3D. This means VRAM compression is not used, which wastes memory for high-resolution textures.

Note: Projector rendering is currently broken, but 3D detection can still be fixed in the meantime.

Steps to reproduce

• Add a MeshInstance3D node with a BoxMesh (to see the lights affecting it).
• Add a OmniLight3D node and enable shadows on it.
• Specify a projector texture in the OmniLight3D properties.
• Add a SpotLight3D node and enable shadows on it.
• Specify a projector texture in the OmniLight3D properties.

Minimal reproduction project

test_projector_detect_3d.zip