### 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)

if (get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_MOTION_VECTORS) {
		p_render_data->scene_data->calculate_motion_vectors = true;
	} else if (render target has velocity override) { // TODO
		p_render_data->scene_data->calculate_motion_vectors = true;
	} else {
		p_render_data->scene_data->calculate_motion_vectors = false;
	}
	*/
	p_render_data->scene_data->calculate_motion_vectors = false; 
	p_render_data->scene_data->directional_light_count = 0;
	p_render_data->scene_data->opaque_prepass_threshold = 0.0;
	
	
	
	
	
	
	Size2i screen_size;
	RID framebuffer;
	bool reverse_cull = p_render_data->scene_data->cam_transform.basis.determinant() < 0;
	bool using_subpass_transparent = true;
	bool using_subpass_post_process = true;
	
	_fill_render_list(RENDER_LIST_OPAQUE, p_render_data, PASS_MODE_COLOR);
	render_list[RENDER_LIST_OPAQUE].sort_by_key();
	render_list[RENDER_LIST_ALPHA].sort_by_reverse_depth_and_priority();
	_fill_element_info(RENDER_LIST_OPAQUE);
	_fill_element_info(RENDER_LIST_ALPHA);
	if (p_render_data->render_info) {
		p_render_data->render_info->info[RS::VIEWPORT_RENDER_INFO_TYPE_VISIBLE][RS::VIEWPORT_RENDER_INFO_DRAW_CALLS_IN_FRAME] = p_render_data->instances->size();