### 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)

inst->flags_cache = flags;
		GeometryInstanceSurfaceDataCache *surf = inst->surface_caches;
		while (surf) {
			surf->sort.uses_lightmap = 0;
			
			if (p_render_data->scene_data->screen_mesh_lod_threshold > 0.0 && mesh_storage->mesh_surface_has_lod(surf->surface)) {
				
				Vector3 lod_support_min = inst->transformed_aabb.get_support(p_render_data->scene_data->cam_transform.basis.get_column(Vector3::AXIS_Z));
				Vector3 lod_support_max = inst->transformed_aabb.get_support(-p_render_data->scene_data->cam_transform.basis.get_column(Vector3::AXIS_Z));
				
				float distance_min = (float)p_render_data->scene_data->cam_transform.origin.distance_to(lod_support_min);
				float distance_max = (float)p_render_data->scene_data->cam_transform.origin.distance_to(lod_support_max);
				float distance = 0.0;
				if (distance_min * distance_max < 0.0) {
					
					distance = 0.0;
				} else if (distance_min >= 0.0) {
					distance = distance_min;
				} else if (distance_max <= 0.0) {
					distance = -distance_max;
				}
				if (p_render_data->scene_data->cam_orthogonal) {
					distance = 1.0;
				}
				uint32_t indices = 0;
				surf->lod_index = mesh_storage->mesh_surface_get_lod(surf->surface, inst->lod_model_scale * inst->lod_bias, distance * p_render_data->scene_data->lod_distance_multiplier, p_render_data->scene_data->screen_mesh_lod_threshold, indices);
				if (p_render_data->render_info) {
					indices = _indices_to_primitives(surf->primitive, indices);
					if (p_render_list == RENDER_LIST_OPAQUE) { 
						p_render_data->render_info->info[RS::VIEWPORT_RENDER_INFO_TYPE_VISIBLE][RS::VIEWPORT_RENDER_INFO_PRIMITIVES_IN_FRAME] += indices;