fix(FreeSql): 修正审计字段赋值逻辑错误

修复审计字段（CreateUserId, CreateUserName, TenantId, UpdateUserId, UpdateUserName）在值为null时才赋值的逻辑错误，之前错误地在值不为null时赋值

Author: igeekfan

src/Directory.Build.props

@@ -15,7 +15,7 @@
         <Copyright>MIT License</Copyright>
         <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
         <PackageProjectUrl>https://github.com/luoyunchong/FreeKit</PackageProjectUrl>
-        <Version>0.0.548</Version>
+        <Version>0.0.549</Version>
     </PropertyGroup>
 
     <ItemGroup>

src/IGeekFan.FreeKit.Extras/FreeSql/FreeSqlExtension.cs

@@ -144,18 +144,18 @@ public static void AuditValue<T>(this AuditValueEventArgs e, ICurrentUser? user)
                 {
                     case "CreateUserId":
                         T? userId = user?.FindUserId<T>();
-                        if (userId.HasValue && e.Value != null) e.Value = userId;
+                        if (userId.HasValue && e.Value == null) e.Value = userId;
                         break;
                     case "CreateUserName":
                         string? userName = user?.UserName;
-                        if (userName.IsNotNullOrWhiteSpace() && e.Value != null) e.Value = userName;
+                        if (userName.IsNotNullOrWhiteSpace() && e.Value == null) e.Value = userName;
                         break;
                     case "CreateTime":
                         e.Value = DateTime.Now;
                         break;
                     case "TenantId":
                         var tenantId = user?.TenantId;
-                        if (tenantId.HasValue && e.Value != null) e.Value = tenantId;
+                        if (tenantId.HasValue && e.Value == null) e.Value = tenantId;
                         break;
                 }
             }
@@ -165,11 +165,11 @@ public static void AuditValue<T>(this AuditValueEventArgs e, ICurrentUser? user)
                 {
                     case "UpdateUserId":
                         T? userId = user?.FindUserId<T>();
-                        if (userId.HasValue && e.Value != null) e.Value = userId;
+                        if (userId.HasValue && e.Value == null) e.Value = userId;
                         break;
                     case "UpdateUserName":
                         string? userName = user?.UserName;
-                        if (userName.IsNotNullOrWhiteSpace() && e.Value != null) e.Value = userName;
+                        if (userName.IsNotNullOrWhiteSpace() && e.Value == null) e.Value = userName;
                         break;
                     case "UpdateTime":
                         e.Value = DateTime.Now;