### 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)

rb_data = rb->get_custom_data(RB_SCOPE_MOBILE);
		}
	}
	
	
	Vector<RD::Uniform> uniforms;
	{
		RD::Uniform u;
		u.binding = 0;
		u.uniform_type = RD::UNIFORM_TYPE_UNIFORM_BUFFER;
		u.append_id(scene_state.uniform_buffers[p_index]);
		uniforms.push_back(u);
	}
	{
		RID radiance_texture;
		if (p_radiance_texture.is_valid()) {
			radiance_texture = p_radiance_texture;
		} else {
			radiance_texture = texture_storage->texture_rd_get_default(is_using_radiance_cubemap_array() ? RendererRD::TextureStorage::DEFAULT_RD_TEXTURE_CUBEMAP_ARRAY_BLACK : RendererRD::TextureStorage::DEFAULT_RD_TEXTURE_CUBEMAP_BLACK);
		}
		RD::Uniform u;
		u.binding = 2;
		u.uniform_type = RD::UNIFORM_TYPE_TEXTURE;
		u.append_id(radiance_texture);
		uniforms.push_back(u);
	}
	{
		RID ref_texture = (p_render_data && p_render_data->reflection_atlas.is_valid()) ? light_storage->reflection_atlas_get_texture(p_render_data->reflection_atlas) : RID();
		RD::Uniform u;
		u.binding = 3;