### Godot version

4.0 Stable

### System information

Ubuntu 22.04

### Issue description

Setting fog_affect_sky = 1 do not have the desired effect when using a Color sky mode. It works properly if we use a procedural sky or the forward+ renderer.

![Screenshot from 2023-03-03 16-50-53](https://user-images.githubusercontent.com/8985409/222870514-0195c4cb-bbca-4e9b-bb6a-6e2a568d2f7b.png)


### Steps to reproduce

Add a sky with a plain color mode like the Clear Color default option. Enable fog and set fog_affect_sky value to 1. Sky is still not affected by fog. 

### Minimal reproduction project
[mobile_fog_sky_bug.zip](https://github.com/godotengine/godot/files/10887265/mobile_fog_sky_bug.zip)


c.push_back(cc); 
				if (rb_data.is_valid()) {
					if (p_render_data->render_buffers->get_msaa_3d() != RS::VIEWPORT_MSAA_DISABLED) {
						c.push_back(clear_color.srgb_to_linear()); 
					}
					if (using_subpass_post_process) {
						c.push_back(Color()); 
					}
				}
			}
			RD::FramebufferFormatID fb_format = RD::get_singleton()->framebuffer_get_format(framebuffer);
			RenderListParameters render_list_params(render_list[RENDER_LIST_OPAQUE].elements.ptr(), render_list[RENDER_LIST_OPAQUE].element_info.ptr(), render_list[RENDER_LIST_OPAQUE].elements.size(), reverse_cull, PASS_MODE_COLOR, rp_uniform_set, spec_constant_base_flags, get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_WIREFRAME, Vector2(), p_render_data->scene_data->lod_distance_multiplier, p_render_data->scene_data->screen_mesh_lod_threshold, p_render_data->scene_data->view_count);
			render_list_params.framebuffer_format = fb_format;
			if ((uint32_t)render_list_params.element_count > render_list_thread_threshold && false) {
				
				
				thread_draw_lists.resize(WorkerThreadPool::get_singleton()->get_thread_count());
				RD::get_singleton()->draw_list_begin_split(framebuffer, thread_draw_lists.size(), thread_draw_lists.ptr(), keep_color ? RD::INITIAL_ACTION_KEEP : RD::INITIAL_ACTION_CLEAR, can_continue_color ? RD::FINAL_ACTION_CONTINUE : RD::FINAL_ACTION_READ, RD::INITIAL_ACTION_CLEAR, can_continue_depth ? RD::FINAL_ACTION_CONTINUE : RD::FINAL_ACTION_READ, c, 1.0, 0);
				WorkerThreadPool::GroupID group_task = WorkerThreadPool::get_singleton()->add_template_group_task(this, &RenderForwardMobile::_render_list_thread_function, &render_list_params, thread_draw_lists.size(), -1, true, SNAME("ForwardMobileRenderList"));
				WorkerThreadPool::get_singleton()->wait_for_group_task_completion(group_task);
			} else {
				
				RD::DrawListID draw_list = RD::get_singleton()->draw_list_begin(framebuffer, keep_color ? RD::INITIAL_ACTION_KEEP : RD::INITIAL_ACTION_CLEAR, can_continue_color ? RD::FINAL_ACTION_CONTINUE : RD::FINAL_ACTION_READ, RD::INITIAL_ACTION_CLEAR, can_continue_depth ? RD::FINAL_ACTION_CONTINUE : RD::FINAL_ACTION_READ, c, 1.0, 0);
				_render_list(draw_list, fb_format, &render_list_params, 0, render_list_params.element_count);
			}
		}
		RD::get_singleton()->draw_command_end_label(); 
		if (draw_sky || draw_sky_fog_only) {
			RD::get_singleton()->draw_command_begin_label("Draw Sky Subpass");