### 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
toggle_button = memnew(Button);
			toggle_button->set_toggle_mode(true);
			toggle_button->set_pressed(true);
			toggle_button->set_text(itos(message_count));
			toggle_button->set_tooltip_text(TTR(p_tooltip));
			
			toggle_button->add_theme_color_override("icon_color_pressed", Color(1, 1, 1, 1));
			toggle_button->set_focus_mode(FOCUS_NONE);
			
			toggle_button->connect("toggled", p_toggled_callback.bind(type));
		}
		int get_message_count() {
			return message_count;
		}
		void set_message_count(int p_count) {
			message_count = p_count;
			toggle_button->set_text(itos(message_count));
		}
		bool is_active() {