### Godot version

4.2.dev1

### System information

Manjaro Linux (DE: Cinnamon v5.8.4) 64 bits

### Issue description

The title already explains it. Take a look at the steps to reproduce below.

### Steps to reproduce

In a GDScript `_ready()` function write this:
```print_rich("[color=red]Red line\n2nd red line[/color]")```

the second line is not red and the output is as follow:
![Capture d’écran du 2023-07-29 05-50-16](https://github.com/godotengine/godot/assets/102065761/554038c6-d128-40c9-8c88-237b44b35b12)

I tested all the the possible BBCodes for the print_rich() method (as stated in the documentation), and of course they all failed.

The RichTextLabel in my projects works as expected.

### Minimal reproduction project

N/A
} break;
		case MSG_TYPE_STD_RICH: {
		} break;
		case MSG_TYPE_ERROR: {
			log->push_color(theme_cache.error_color);
			Ref<Texture2D> icon = theme_cache.error_icon;
			log->add_image(icon);
			log->add_text(" ");
			tool_button->set_icon(icon);
		} break;
		case MSG_TYPE_WARNING: {
			log->push_color(theme_cache.warning_color);
			Ref<Texture2D> icon = theme_cache.warning_icon;
			log->add_image(icon);
			log->add_text(" ");
			tool_button->set_icon(icon);
		} break;
		case MSG_TYPE_EDITOR: {
			
			log->push_color(theme_cache.message_color);
		} break;
	}
	
	if (collapse && p_message.count > 1) {
		log->push_bold();
		log->add_text(vformat("(%s) ", itos(p_message.count)));
		log->pop();
	}
	if (p_message.type == MSG_TYPE_STD_RICH) {
		log->append_text(p_message.text);