### Godot version

4.1.beta (7b1387ff2)

### System information

Mageia 9, Linux

### Issue description

When opening an empty project in latest `master`, I get these errors:
```
ERROR: Index p_idx = -1 is out of bounds (edited_scene.size() = 1).
   at: get_scene_path (editor/scu/../editor_data.cpp:880)
ERROR: Index p_idx = -1 is out of bounds (edited_scene.size() = 1).
   at: check_and_update_scene (editor/scu/../editor_data.cpp:683)
ERROR: Index p_idx = -1 is out of bounds (edited_scene.size() = 1).
   at: set_edited_scene (editor/scu/../editor_data.cpp:745)
```

Possibly related to recent changes to restore past sessions, but there's nothing to restore in this case?

### Steps to reproduce

- Create a new project, edit it
- Quit to project manager
- Re-open the newly created project -> errors

### Minimal reproduction project

Empty project.
#include "editor_node.h"
#include "core/config/project_settings.h"
#include "core/input/input.h"
#include "core/io/config_file.h"
#include "core/io/file_access.h"
#include "core/io/resource_loader.h"
#include "core/io/resource_saver.h"
#include "core/object/class_db.h"
#include "core/object/message_queue.h"
#include "core/os/keyboard.h"
#include "core/os/os.h"
#include "core/os/time.h"
#include "core/string/print_string.h"
#include "core/string/translation.h"
#include "core/version.h"
#include "main/main.h"
#include "scene/gui/color_picker.h"