### 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)

return RID();
}
RID RenderForwardMobile::_render_buffers_get_velocity_texture(Ref<RenderSceneBuffersRD> p_render_buffers) {
	return RID();
}
_FORCE_INLINE_ static uint32_t _indices_to_primitives(RS::PrimitiveType p_primitive, uint32_t p_indices) {
	static const uint32_t divisor[RS::PRIMITIVE_MAX] = { 1, 2, 1, 3, 1 };
	static const uint32_t subtractor[RS::PRIMITIVE_MAX] = { 0, 0, 1, 0, 1 };
	return (p_indices - subtractor[p_primitive]) / divisor[p_primitive];
}
void RenderForwardMobile::_fill_render_list(RenderListType p_render_list, const RenderDataRD *p_render_data, PassMode p_pass_mode, bool p_append) {
	RendererRD::MeshStorage *mesh_storage = RendererRD::MeshStorage::get_singleton();
	if (p_render_list == RENDER_LIST_OPAQUE) {
		scene_state.used_sss = false;
		scene_state.used_screen_texture = false;
		scene_state.used_normal_texture = false;
		scene_state.used_depth_texture = false;
	}
	uint32_t lightmap_captures_used = 0;
	Plane near_plane(-p_render_data->scene_data->cam_transform.basis.get_column(Vector3::AXIS_Z), p_render_data->scene_data->cam_transform.origin);
	near_plane.d += p_render_data->scene_data->cam_projection.get_z_near();
	float z_max = p_render_data->scene_data->cam_projection.get_z_far() - p_render_data->scene_data->cam_projection.get_z_near();
	RenderList *rl = &render_list[p_render_list];
	
	_update_dirty_geometry_instances();
	if (!p_append) {
		rl->clear();
		if (p_render_list == RENDER_LIST_OPAQUE) {
			render_list[RENDER_LIST_ALPHA].clear(); 
		}