### Godot version

4.1.1.stable, 4.2.dev (2282fc5de)

### System information

Arch Linux - X11 - GLES3 (Compatibility) - NVIDIA GeForce RTX 3060 Ti (nvidia; 535.104.05) - 13th Gen Intel(R) Core(TM) i5-13400F (16 Threads)

### Issue description

When using Compatibility renderer, adjusting the Alpha component of clear color affects 2D editor content.

This does not happen when using Forward+ or Mobile renderer. Does not affect 3D editor and the running game.


https://github.com/godotengine/godot/assets/372476/e398522e-590a-4832-959f-ea8ba8e71c5d



### Steps to reproduce

1. Create a project using Compatibility renderer.
2. Adjust the clear color's alpha component in Project Settings.

### Minimal reproduction project

N/A
}
			_render_items(p_to_render_target, item_count, canvas_transform_inverse, p_light_list, r_sdf_used, true);
			item_count = 0;
			if (ci->canvas_group->blur_mipmaps) {
				texture_storage->render_target_gen_back_buffer_mipmaps(p_to_render_target, ci->global_rect_cache);
			}
			canvas_group_owner = nullptr;
			
			backbuffer_cleared = false;
			
			ci->use_canvas_group = true;
		} else {
			ci->use_canvas_group = false;
		}
		if (backbuffer_copy) {
			if (update_skeletons) {
				mesh_storage->update_mesh_instances();
				update_skeletons = false;
			}
			
			_render_items(p_to_render_target, item_count, canvas_transform_inverse, p_light_list, r_sdf_used);
			item_count = 0;
			texture_storage->render_target_copy_to_back_buffer(p_to_render_target, back_buffer_rect, backbuffer_gen_mipmaps);
			backbuffer_copy = false;
			material_screen_texture_cached = true; 
			material_screen_texture_mipmaps_cached = backbuffer_gen_mipmaps;
			backbuffer_gen_mipmaps = false;
		}
		if (backbuffer_gen_mipmaps) {
			texture_storage->render_target_gen_back_buffer_mipmaps(p_to_render_target, back_buffer_rect);