Workaround for Unity 2022.2 bug where scene asset labels are removed on save

SceneLabelsPreserver.cs

using UnityEngine;
using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine.SceneManagement;
using System.IO;

/// <summary>
/// Workaround for bug: https://issuetracker.unity3d.com/issues/scene-asset-label-disappears-when-the-scene-is-saved
/// Saves the scene's label before and re-applies them after saving.
/// Will log if the labels are preserved and this workaround is no longer necessary.
/// Unfortunately, will prompt to reload the scene after saving. :(
/// </summary>
public class SceneLabelsPreserver
{
    [InitializeOnLoadMethod]
    static void Initialize()
    {
        EditorSceneManager.sceneSaving += OnSavingScene;
        EditorSceneManager.sceneSaved += OnSavedScene;
    }

    static string currentPath;
    static string[] currentLabels;

    static void OnSavingScene(Scene scene, string path)
    {
        if (!File.Exists(path))
            return;

        var guid = AssetDatabase.GUIDFromAssetPath(path);
        if (guid.Empty()) {
            Debug.LogWarning($"SceneLabelsPreserver.OnSavingScene: Could not get GUID for scene path '{path}'");
            return;
        }

        currentPath = path;
        currentLabels = AssetDatabase.GetLabels(guid);
    }

    static void OnSavedScene(Scene scene)
    {
        if (currentPath == null || currentLabels == null || currentLabels.Length == 0)
            return;

        if (scene.path != currentPath) {
            Debug.LogError($"SceneLabelsPreserver.OnSavedScene: Unbalanced OnSavingScene/OnSavedScene calls ({currentPath} vs {scene.path})");
            return;
        }

        var guid = AssetDatabase.GUIDFromAssetPath(scene.path);
        if (guid.Empty()) {
            Debug.LogWarning($"SceneLabelsPreserver.OnSavingScene: Could not get GUID for scene path '{scene.path}'");
            return;
        }

        var labels = AssetDatabase.GetLabels(guid);
        if (labels.Length != 0) {
            Debug.Log($"SceneLabelsPreserver: Scene labels appear to be preserved, maybe this fix is no longer needed? (for {scene.path})");
            return;
        }

        var sceneAsset = AssetDatabase.LoadAssetAtPath<SceneAsset>(scene.path);
        if (sceneAsset == null) {
            Debug.LogError($"SceneLabelsPreserver.OnSavedScene: Could not load scene asset at path '{scene.path}'");
            return;
        }

        AssetDatabase.SetLabels(sceneAsset, currentLabels);
        AssetDatabase.SaveAssets();

        currentPath = null;
        currentLabels = null;
    }
}