### Godot version

4.1.1

### System information

windows 11, mobile renderer

### Issue description

On Mobile Vulkan renderer, the clear color is 50% lighter than expected

See steps to reproduce and Minimal reproduction project below.

The box and background have the same color on Forward+ and compatibility, but not on Mobile
happens also in runtime on exported project, not only in editor preview

Images of the same scene from
compatibility:
![compatibility](https://github.com/godotengine/godot/assets/11915378/a874fa86-c16f-43ef-aed7-c2066b770ac1)
Forward+:
![forward](https://github.com/godotengine/godot/assets/11915378/e416f9a6-dfd4-4c47-bbc2-b552ca58f83c)
Mobile:
![mobile](https://github.com/godotengine/godot/assets/11915378/e28e2db8-f7c3-47e2-8c0a-44ce937c9270)


### Steps to reproduce

 - add a CSGBox3D with "unshaded" shading, and albedo of #545454
 - add environment with Background = Custom color and color of #545454

Box and background are not the same color

### Minimal reproduction project

[bg_color.zip](https://github.com/godotengine/godot/files/12174822/bg_color.zip)

u.uniform_type = RD::UNIFORM_TYPE_STORAGE_BUFFER;
			u.append_id(RendererRD::LightStorage::get_singleton()->get_reflection_probe_buffer());
			uniforms.push_back(u);
		}
		{
			RD::Uniform u;
			u.binding = 8;
			u.uniform_type = RD::UNIFORM_TYPE_UNIFORM_BUFFER;
			u.append_id(RendererRD::LightStorage::get_singleton()->get_directional_light_buffer());
			uniforms.push_back(u);
		}
		{
			RD::Uniform u;
			u.binding = 9;
			u.uniform_type = RD::UNIFORM_TYPE_STORAGE_BUFFER;
			u.append_id(scene_state.lightmap_buffer);
			uniforms.push_back(u);
		}
		{
			RD::Uniform u;
			u.binding = 10;
			u.uniform_type = RD::UNIFORM_TYPE_STORAGE_BUFFER;
			u.append_id(scene_state.lightmap_capture_buffer);
			uniforms.push_back(u);
		}
		{
			RD::Uniform u;
			u.binding = 11;
			u.uniform_type = RD::UNIFORM_TYPE_TEXTURE;
			RID decal_atlas = RendererRD::TextureStorage::get_singleton()->decal_atlas_get_texture();