### 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.
Ref<InputEventMouseButton> mb = p_input;
	if (mb.is_valid()) {
		if (scene_tabs->get_hovered_tab() >= 0) {
			if (mb->get_button_index() == MouseButton::MIDDLE && mb->is_pressed()) {
				_scene_tab_closed(scene_tabs->get_hovered_tab());
			}
		} else {
			if (mb->get_button_index() == MouseButton::LEFT && mb->is_double_click()) {
				_menu_option_confirm(FILE_NEW_SCENE, true);
			}
		}
		if (mb->get_button_index() == MouseButton::RIGHT && mb->is_pressed()) {
			
			scene_tabs_context_menu->clear();
			scene_tabs_context_menu->reset_size();
			scene_tabs_context_menu->add_shortcut(ED_GET_SHORTCUT("editor/new_scene"), FILE_NEW_SCENE);
			if (scene_tabs->get_hovered_tab() >= 0) {
				scene_tabs_context_menu->add_shortcut(ED_GET_SHORTCUT("editor/save_scene"), FILE_SAVE_SCENE);
				scene_tabs_context_menu->add_shortcut(ED_GET_SHORTCUT("editor/save_scene_as"), FILE_SAVE_AS_SCENE);
			}
			scene_tabs_context_menu->add_shortcut(ED_GET_SHORTCUT("editor/save_all_scenes"), FILE_SAVE_ALL_SCENES);
			if (scene_tabs->get_hovered_tab() >= 0) {
				scene_tabs_context_menu->add_separator();
				scene_tabs_context_menu->add_item(TTR("Show in FileSystem"), FILE_SHOW_IN_FILESYSTEM);
				scene_tabs_context_menu->add_item(TTR("Play This Scene"), FILE_RUN_SCENE);
				scene_tabs_context_menu->add_separator();
				scene_tabs_context_menu->add_shortcut(ED_GET_SHORTCUT("editor/close_scene"), FILE_CLOSE);
				scene_tabs_context_menu->set_item_text(scene_tabs_context_menu->get_item_index(FILE_CLOSE), TTR("Close Tab"));