### 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
if (!is_inside_tree()) {
		
		return;
	}
	if (unlikely(log->is_updating())) {
		
		return;
	}
	
	bool filter_active = type_filter_map[p_message.type]->is_active();
	String search_text = search_box->get_text();
	bool search_match = search_text.is_empty() || p_message.text.findn(search_text) > -1;
	if (!filter_active || !search_match) {
		return;
	}
	if (p_replace_previous) {
		
		
		
		log->remove_paragraph(log->get_paragraph_count() - 2);
	}
	switch (p_message.type) {
		case MSG_TYPE_STD: {