Apply suggestions from code review

Co-Authored-By: Claus Vium <cvium@users.noreply.github.com>
Co-Authored-By: Bond-009 <bond.009@outlook.com>

Emby.Server.Implementations/Library/InvalidAuthProvider.cs

@@ -9,7 +9,7 @@ namespace Emby.Server.Implementations.Library
 {
     public class InvalidAuthProvider : IAuthenticationProvider
     {
-        public string Name => "InvalidorMissingAuthenticationProvider";
+        public string Name => "InvalidOrMissingAuthenticationProvider";
 
         public bool IsEnabled => true;
 
@@ -25,7 +25,7 @@ namespace Emby.Server.Implementations.Library
 
         public Task ChangePassword(User user, string newPassword)
         {
-            return Task.FromResult(true);
+            return Task.CompletedTask;
         }
 
         public void ChangeEasyPassword(User user, string newPassword, string newPasswordHash)
@@ -35,12 +35,12 @@ namespace Emby.Server.Implementations.Library
 
         public string GetPasswordHash(User user)
         {
-            return "";
+            return string.Empty;
         }
 
         public string GetEasyPasswordHash(User user)
         {
-            return "";
+            return string.Empty;
         }
     }
 }

Emby.Server.Implementations/Library/UserManager.cs

@@ -313,8 +313,7 @@ namespace Emby.Server.Implementations.Library
 
                     if (authenticationProvider.GetType() != typeof(InvalidAuthProvider))
                     {
-                        var hasNewUserPolicy = authenticationProvider as IHasNewUserPolicy;
+                        if (authenticationProvider is IHasNewUserPolicy hasNewUserPolicy)
-                        if (hasNewUserPolicy != null)
                         {
                             var policy = hasNewUserPolicy.GetNewUserPolicy();
                             UpdateUserPolicy(user, policy, true);
@@ -408,7 +407,7 @@ namespace Emby.Server.Implementations.Library
             if (providers.Length == 0)
             {
                 // Assign the user to the InvalidAuthProvider since no configured auth provider was valid/found
-                _logger.LogWarning("User {0} was found with invalid/missing Authentication Provider {1}. Assigning user to InvalidAuthProvider until this is corrected", user.Name, user.Policy.AuthenticationProviderId);
+                _logger.LogWarning("User {UserName} was found with invalid/missing Authentication Provider {AuthenticationProviderId}. Assigning user to InvalidAuthProvider until this is corrected", user.Name, user.Policy.AuthenticationProviderId);
                 providers = new IAuthenticationProvider[] { _invalidAuthProvider };
             }