Editing light_specular is not available in the DirectionalLight3D inspector settings

[mishkarch]

Tested versions

4.2.2 stable

System information

Windows (I think it's not matter)

Issue description

Hello. According to the documentation, Light3D has a light_specular property. DirectionalLight3D inherits from it, however, when added to the scene, in the inspector properties it is not possible to edit light_specular. (At the same time, the official tutorial on fake global illumination directly advises creating a DirectionalLight3D and setting to zero its specular.)
OmniLight3D and SpotLight3D are fine in this regard.

Steps to reproduce

Create a scene, add DirectionalLight3D.

Minimal reproduction project (MRP)

N/A

[Chaosus]

Looks like it's not implemented:

godot/scene/3d/light_3d.cpp

Lines 535 to 538 in 71699e0

	if (p_property.name == "light_size" || p_property.name == "light_projector" || p_property.name == "light_specular") {
	// Not implemented in DirectionalLight3D (`light_size` is replaced by `light_angular_distance`).
	p_property.usage = PROPERTY_USAGE_NONE;
	}

[Calinou]

Thanks for the report! Consolidating in #80737.