### 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)

scene_data.screen_mesh_lod_threshold = p_screen_mesh_lod_threshold;
	}
	PassMode pass_mode = p_use_dp ? PASS_MODE_SHADOW_DP : PASS_MODE_SHADOW;
	uint32_t render_list_from = render_list[RENDER_LIST_SECONDARY].elements.size();
	_fill_render_list(RENDER_LIST_SECONDARY, &render_data, pass_mode, true);
	uint32_t render_list_size = render_list[RENDER_LIST_SECONDARY].elements.size() - render_list_from;
	render_list[RENDER_LIST_SECONDARY].sort_by_key_range(render_list_from, render_list_size);
	_fill_element_info(RENDER_LIST_SECONDARY, render_list_from, render_list_size);
	{
		
		bool flip_cull = p_use_dp_flip;
		if (p_flip_y) {
			flip_cull = !flip_cull;
		}
		shadow_pass.element_from = render_list_from;
		shadow_pass.element_count = render_list_size;
		shadow_pass.flip_cull = flip_cull;
		shadow_pass.pass_mode = pass_mode;
		shadow_pass.rp_uniform_set = RID(); 
		shadow_pass.camera_plane = p_camera_plane;
		shadow_pass.screen_mesh_lod_threshold = scene_data.screen_mesh_lod_threshold;
		shadow_pass.lod_distance_multiplier = scene_data.lod_distance_multiplier;
		shadow_pass.framebuffer = p_framebuffer;
		shadow_pass.initial_depth_action = p_begin ? (p_clear_region ? RD::INITIAL_ACTION_CLEAR_REGION : RD::INITIAL_ACTION_CLEAR) : (p_clear_region ? RD::INITIAL_ACTION_CLEAR_REGION_CONTINUE : RD::INITIAL_ACTION_CONTINUE);
		shadow_pass.final_depth_action = p_end ? RD::FINAL_ACTION_READ : RD::FINAL_ACTION_CONTINUE;
		shadow_pass.rect = p_rect;
		scene_state.shadow_passes.push_back(shadow_pass);
	}
}
void RenderForwardMobile::_render_shadow_process() {