### 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
_new_batch(r_batch_broken);
					state.canvas_instance_batches[state.current_batch_index].repeat = RenderingServer::CanvasItemTextureRepeat::CANVAS_ITEM_TEXTURE_REPEAT_ENABLED;
				}
				if (rect->texture != state.canvas_instance_batches[state.current_batch_index].tex || state.canvas_instance_batches[state.current_batch_index].command_type != Item::Command::TYPE_RECT) {
					_new_batch(r_batch_broken);
					state.canvas_instance_batches[state.current_batch_index].tex = rect->texture;
					state.canvas_instance_batches[state.current_batch_index].command_type = Item::Command::TYPE_RECT;
					state.canvas_instance_batches[state.current_batch_index].command = c;
					state.canvas_instance_batches[state.current_batch_index].shader_variant = CanvasShaderGLES3::MODE_QUAD;
				}
				_prepare_canvas_texture(rect->texture, state.canvas_instance_batches[state.current_batch_index].filter, state.canvas_instance_batches[state.current_batch_index].repeat, r_index, texpixel_size);
				Rect2 src_rect;
				Rect2 dst_rect;
				if (rect->texture != RID()) {
					src_rect = (rect->flags & CANVAS_RECT_REGION) ? Rect2(rect->source.position * texpixel_size, rect->source.size * texpixel_size) : Rect2(0, 0, 1, 1);
					dst_rect = Rect2(rect->rect.position, rect->rect.size);
					if (dst_rect.size.width < 0) {
						dst_rect.position.x += dst_rect.size.width;
						dst_rect.size.width *= -1;
					}
					if (dst_rect.size.height < 0) {
						dst_rect.position.y += dst_rect.size.height;
						dst_rect.size.height *= -1;
					}
					if (rect->flags & CANVAS_RECT_FLIP_H) {
						src_rect.size.x *= -1;
						state.instance_data_array[r_index].flags |= FLAGS_FLIP_H;
					}
					if (rect->flags & CANVAS_RECT_FLIP_V) {
						src_rect.size.y *= -1;