### 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)

shader_version = SceneShaderForwardMobile::SHADER_VERSION_SHADOW_PASS_DP;
			} break;
			case PASS_MODE_DEPTH_MATERIAL: {
				ERR_FAIL_COND_MSG(p_params->view_count > 1, "Multiview not supported for material pass");
				shader_version = SceneShaderForwardMobile::SHADER_VERSION_DEPTH_PASS_WITH_MATERIAL;
			} break;
		}
		PipelineCacheRD *pipeline = nullptr;
		pipeline = &shader->pipelines[cull_variant][primitive][shader_version];
		RD::VertexFormatID vertex_format = -1;
		RID vertex_array_rd;
		RID index_array_rd;
		
		if (surf->owner->mesh_instance.is_valid()) {
			mesh_storage->mesh_instance_surface_get_vertex_arrays_and_format(surf->owner->mesh_instance, surf->surface_index, pipeline->get_vertex_input_mask(), false, vertex_array_rd, vertex_format);
		} else {
			mesh_storage->mesh_surface_get_vertex_arrays_and_format(mesh_surface, pipeline->get_vertex_input_mask(), false, vertex_array_rd, vertex_format);
		}
		index_array_rd = mesh_storage->mesh_surface_get_index_array(mesh_surface, element_info.lod_index);
		if (prev_vertex_array_rd != vertex_array_rd) {
			RD::get_singleton()->draw_list_bind_vertex_array(draw_list, vertex_array_rd);
			prev_vertex_array_rd = vertex_array_rd;
		}
		if (prev_index_array_rd != index_array_rd) {
			if (index_array_rd.is_valid()) {
				RD::get_singleton()->draw_list_bind_index_array(draw_list, index_array_rd);
			}
			prev_index_array_rd = index_array_rd;
		}
		RID pipeline_rd = pipeline->get_render_pipeline(vertex_format, framebuffer_format, p_params->force_wireframe, p_params->subpass, base_spec_constants);