### 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)

thread_draw_lists.resize(WorkerThreadPool::get_singleton()->get_thread_count());
				RD::get_singleton()->draw_list_switch_to_next_pass_split(thread_draw_lists.size(), thread_draw_lists.ptr());
				render_list_params.subpass = RD::get_singleton()->draw_list_get_current_pass();
				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("ForwardMobileRenderSubpass"));
				WorkerThreadPool::get_singleton()->wait_for_group_task_completion(group_task);
			} else {
				
				RD::DrawListID draw_list = RD::get_singleton()->draw_list_switch_to_next_pass();
				render_list_params.subpass = RD::get_singleton()->draw_list_get_current_pass();
				_render_list(draw_list, fb_format, &render_list_params, 0, render_list_params.element_count);
			}
			RD::get_singleton()->draw_command_end_label(); 
			
			
			if (rb_data.is_valid() && using_subpass_post_process) {
				_post_process_subpass(p_render_data->render_buffers->get_internal_texture(), framebuffer, p_render_data);
			}
			RD::get_singleton()->draw_command_end_label(); 
			RD::get_singleton()->draw_list_end(RD::BARRIER_MASK_ALL_BARRIERS);
		} else {
			RENDER_TIMESTAMP("Render Transparent");
			if (rb_data.is_valid()) {
				framebuffer = rb_data->get_color_fbs(RenderBufferDataForwardMobile::FB_CONFIG_ONE_PASS);
			}
			
			
			RD::FramebufferFormatID fb_format = RD::get_singleton()->framebuffer_get_format(framebuffer);
			RenderListParameters render_list_params(render_list[RENDER_LIST_ALPHA].elements.ptr(), render_list[RENDER_LIST_ALPHA].element_info.ptr(), render_list[RENDER_LIST_ALPHA].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;