Fix some warnings

Emby.Server.Implementations/AppBase/BaseConfigurationManager.cs

@@ -25,6 +25,11 @@ namespace Emby.Server.Implementations.AppBase
 
         private readonly ConcurrentDictionary<string, object> _configurations = new ConcurrentDictionary<string, object>();
 
+        /// <summary>
+        /// The _configuration sync lock.
+        /// </summary>
+        private readonly object _configurationSyncLock = new object();
+
         private ConfigurationStore[] _configurationStores = Array.Empty<ConfigurationStore>();
         private IConfigurationFactory[] _configurationFactories = Array.Empty<IConfigurationFactory>();
 
@@ -33,11 +38,6 @@ namespace Emby.Server.Implementations.AppBase
         /// </summary>
         private bool _configurationLoaded;
 
-        /// <summary>
-        /// The _configuration sync lock.
-        /// </summary>
-        private readonly object _configurationSyncLock = new object();
-
         /// <summary>
         /// The _configuration.
         /// </summary>

Emby.Server.Implementations/AppBase/ConfigurationHelper.cs

@@ -33,7 +33,8 @@ namespace Emby.Server.Implementations.AppBase
             }
             catch (Exception)
             {
-                configuration = Activator.CreateInstance(type) ?? throw new ArgumentException($"Provided path ({type}) is not valid.", nameof(type));
+                // Note: CreateInstance returns null for Nullable<T>, e.g. CreateInstance(typeof(int?)) returns null.
+                configuration = Activator.CreateInstance(type)!;
             }
 
             using var stream = new MemoryStream(buffer?.Length ?? 0);