### 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.
ERR_FAIL_COND(p_event.is_null());
	Ref<InputEventKey> k = p_event;
	if ((k.is_valid() && k->is_pressed() && !k->is_echo()) || Object::cast_to<InputEventShortcut>(*p_event)) {
		EditorPlugin *old_editor = editor_plugin_screen;
		if (ED_IS_SHORTCUT("editor/next_tab", p_event)) {
			int next_tab = editor_data.get_edited_scene() + 1;
			next_tab %= editor_data.get_edited_scene_count();
			_scene_tab_changed(next_tab);
		}
		if (ED_IS_SHORTCUT("editor/prev_tab", p_event)) {
			int next_tab = editor_data.get_edited_scene() - 1;
			next_tab = next_tab >= 0 ? next_tab : editor_data.get_edited_scene_count() - 1;
			_scene_tab_changed(next_tab);
		}
		if (ED_IS_SHORTCUT("editor/filter_files", p_event)) {
			FileSystemDock::get_singleton()->focus_on_filter();
		}
		if (ED_IS_SHORTCUT("editor/editor_2d", p_event)) {
			editor_select(EDITOR_2D);
		} else if (ED_IS_SHORTCUT("editor/editor_3d", p_event)) {
			editor_select(EDITOR_3D);
		} else if (ED_IS_SHORTCUT("editor/editor_script", p_event)) {
			editor_select(EDITOR_SCRIPT);
		} else if (ED_IS_SHORTCUT("editor/editor_help", p_event)) {
			emit_signal(SNAME("request_help_search"), "");
		} else if (ED_IS_SHORTCUT("editor/editor_assetlib", p_event) && AssetLibraryEditorPlugin::is_available()) {
			editor_select(EDITOR_ASSETLIB);
		} else if (ED_IS_SHORTCUT("editor/editor_next", p_event)) {
			_editor_select_next();