### 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
#ifndef EDITOR_LOG_H
#define EDITOR_LOG_H
#include "core/os/thread.h"
#include "scene/gui/box_container.h"
#include "scene/gui/button.h"
#include "scene/gui/label.h"
#include "scene/gui/line_edit.h"
#include "scene/gui/panel_container.h"
#include "scene/gui/rich_text_label.h"
#include "scene/gui/texture_button.h"
#include "scene/gui/texture_rect.h"
class UndoRedo;
class EditorLog : public HBoxContainer {
	GDCLASS(EditorLog, HBoxContainer);
public:
	enum MessageType {
		MSG_TYPE_STD,
		MSG_TYPE_ERROR,
		MSG_TYPE_STD_RICH,
		MSG_TYPE_WARNING,
		MSG_TYPE_EDITOR,
	};
private:
	struct LogMessage {
		String text;
		MessageType type;
		int count = 1;
		LogMessage() {}