### 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.
default_layout->set_value(docks_section, "dock_3", "Scene,Import");
	default_layout->set_value(docks_section, "dock_4", "FileSystem");
	default_layout->set_value(docks_section, "dock_5", "Inspector,Node,History");
	for (int i = 0; i < vsplits.size(); i++) {
		default_layout->set_value(docks_section, "dock_split_" + itos(i + 1), 0);
	}
	default_layout->set_value(docks_section, "dock_hsplit_1", 0);
	default_layout->set_value(docks_section, "dock_hsplit_2", 270 * EDSCALE);
	default_layout->set_value(docks_section, "dock_hsplit_3", -270 * EDSCALE);
	default_layout->set_value(docks_section, "dock_hsplit_4", 0);
	_update_layouts_menu();
	
	bottom_panel = memnew(PanelContainer);
	bottom_panel->add_theme_style_override("panel", gui_base->get_theme_stylebox(SNAME("BottomPanel"), SNAME("EditorStyles")));
	center_split->add_child(bottom_panel);
	center_split->set_dragger_visibility(SplitContainer::DRAGGER_HIDDEN);
	bottom_panel_vb = memnew(VBoxContainer);
	bottom_panel->add_child(bottom_panel_vb);
	bottom_panel_hb = memnew(HBoxContainer);
	bottom_panel_hb->set_custom_minimum_size(Size2(0, 24 * EDSCALE)); 
	bottom_panel_vb->add_child(bottom_panel_hb);
	bottom_panel_hb_editors = memnew(HBoxContainer);
	bottom_panel_hb_editors->set_h_size_flags(Control::SIZE_EXPAND_FILL);
	bottom_panel_hb->add_child(bottom_panel_hb_editors);
	editor_toaster = memnew(EditorToaster);
	bottom_panel_hb->add_child(editor_toaster);
	VBoxContainer *version_info_vbc = memnew(VBoxContainer);
	bottom_panel_hb->add_child(version_info_vbc);