Fix realm refetch operations potentially being unsafe

As seen in test failure https://github.com/ppy/osu/runs/6357384721?check_suite_focus=true.

osu.Game/Database/RealmAccess.cs

@@ -344,6 +344,26 @@ namespace osu.Game.Database
             }
         }
 
+        /// <summary>
+        /// Write changes to realm.
+        /// </summary>
+        /// <param name="action">The work to run.</param>
+        public T Write<T>(Func<Realm, T> action)
+        {
+            if (ThreadSafety.IsUpdateThread)
+            {
+                total_writes_update.Value++;
+                return Realm.Write(action);
+            }
+            else
+            {
+                total_writes_async.Value++;
+
+                using (var realm = getRealmInstance())
+                    return realm.Write(action);
+            }
+        }
+
         /// <summary>
         /// Write changes to realm.
         /// </summary>