### 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.
dock_tab_move_left->set_flat(true);
	if (gui_base->is_layout_rtl()) {
		dock_tab_move_left->set_icon(theme->get_icon(SNAME("Forward"), SNAME("EditorIcons")));
	} else {
		dock_tab_move_left->set_icon(theme->get_icon(SNAME("Back"), SNAME("EditorIcons")));
	}
	dock_tab_move_left->set_focus_mode(Control::FOCUS_NONE);
	dock_tab_move_left->connect("pressed", callable_mp(this, &EditorNode::_dock_move_left));
	dock_hb->add_child(dock_tab_move_left);
	Label *dock_label = memnew(Label);
	dock_label->set_text(TTR("Dock Position"));
	dock_label->set_h_size_flags(Control::SIZE_EXPAND_FILL);
	dock_label->set_horizontal_alignment(HORIZONTAL_ALIGNMENT_CENTER);
	dock_hb->add_child(dock_label);
	dock_tab_move_right = memnew(Button);
	dock_tab_move_right->set_flat(true);
	if (gui_base->is_layout_rtl()) {
		dock_tab_move_right->set_icon(theme->get_icon(SNAME("Back"), SNAME("EditorIcons")));
	} else {
		dock_tab_move_right->set_icon(theme->get_icon(SNAME("Forward"), SNAME("EditorIcons")));
	}
	dock_tab_move_right->set_focus_mode(Control::FOCUS_NONE);
	dock_tab_move_right->connect("pressed", callable_mp(this, &EditorNode::_dock_move_right));
	dock_hb->add_child(dock_tab_move_right);
	dock_vb->add_child(dock_hb);
	dock_select = memnew(Control);
	dock_select->set_custom_minimum_size(Size2(128, 64) * EDSCALE);
	dock_select->connect("gui_input", callable_mp(this, &EditorNode::_dock_select_input));
	dock_select->connect("draw", callable_mp(this, &EditorNode::_dock_select_draw));
	dock_select->connect("mouse_exited", callable_mp(this, &EditorNode::_dock_popup_exit));