Enable nullable for UserItemData

MetadataResult.GetOrAddUserData doesn't ever get used and is probably broken since the migration to .NET Core as it still expects a Guid for userId

MediaBrowser.Controller/Entities/UserItemData.cs

@@ -1,5 +1,3 @@
-#nullable disable
-
 #pragma warning disable CS1591
 
 using System;
@@ -19,17 +17,11 @@ namespace MediaBrowser.Controller.Entities
         /// </summary>
         private double? _rating;
 
-        /// <summary>
-        /// Gets or sets the user id.
-        /// </summary>
-        /// <value>The user id.</value>
-        public Guid UserId { get; set; }
-
         /// <summary>
         /// Gets or sets the key.
         /// </summary>
         /// <value>The key.</value>
-        public string Key { get; set; }
+        public required string Key { get; set; }
 
         /// <summary>
         /// Gets or sets the users 0-10 rating.

MediaBrowser.Controller/Providers/MetadataResult.cs

@@ -2,9 +2,7 @@
 
 #pragma warning disable CA1002, CA2227, CS1591
 
-using System;
 using System.Collections.Generic;
-using System.Globalization;
 using MediaBrowser.Controller.Entities;
 using MediaBrowser.Model.Entities;
 
@@ -33,8 +31,6 @@ namespace MediaBrowser.Controller.Providers
             set => _remoteImages = value;
         }
 
-        public List<UserItemData> UserDataList { get; set; }
-
         public List<PersonInfo> People { get; set; }
 
         public bool HasMetadata { get; set; }
@@ -68,32 +64,5 @@ namespace MediaBrowser.Controller.Providers
                 People.Clear();
             }
         }
-
-        public UserItemData GetOrAddUserData(string userId)
-        {
-            UserDataList ??= new List<UserItemData>();
-
-            UserItemData userData = null;
-
-            foreach (var i in UserDataList)
-            {
-                if (string.Equals(userId, i.UserId.ToString("N", CultureInfo.InvariantCulture), StringComparison.OrdinalIgnoreCase))
-                {
-                    userData = i;
-                }
-            }
-
-            if (userData is null)
-            {
-                userData = new UserItemData()
-                {
-                    UserId = new Guid(userId)
-                };
-
-                UserDataList.Add(userData);
-            }
-
-            return userData;
-        }
     }
 }