Revert #13281 and only set UpgradeUnattended value to true for new projects (#14764)

* Revert "Change default UpgradeUnattended value to true (#13281)"

This reverts commit e5d6372dbd.

* Set UpgradeUnattended value to true for new projects

src/Umbraco.Core/Configuration/Models/UnattendedSettings.cs

@@ -13,7 +13,7 @@ namespace Umbraco.Cms.Core.Configuration.Models;
 public class UnattendedSettings
 {
     private const bool StaticInstallUnattended = false;
-    private const bool StaticUpgradeUnattended = true;
+    private const bool StaticUpgradeUnattended = false;
 
     /// <summary>
     ///     Gets or sets a value indicating whether unattended installs are enabled.

templates/UmbracoProject/appsettings.json

@@ -33,6 +33,9 @@
         "ContentVersionCleanupPolicy": {
           "EnableCleanup": true
         }
+      },
+      "Unattended": {
+        "UpgradeUnattended": true
       }
     }
   }