[AC-358] Server changes for self host subscription page changes (#2826)

* [AC-358] Add constant for grace period length

* [AC-358] Add SubscriptionExpiration to OrganizationLicense.cs and increment Current_License_File_Version

* [AC-358] Update org subscription response model

- Add new SelfHostSubscriptionExpiration field that does not include a grace period
- Add optional License argument to constructor for self host responses
- Use the License, if available, to populate the expiration/subscription expiration fields
- Maintain backwards compatability by falling back to organization expiration date

* [AC-358] Read organization license file for self hosted subscription response

* [AC-358] Decrement current license file version and add comment documenting why

* [AC-358] Clarify name for new expiration without grace period field

src/Core/Constants.cs

@@ -13,6 +13,12 @@ public static class Constants
     public const long FileSize501mb = 501L * 1024L * 1024L;
     public const string DatabaseFieldProtectorPurpose = "DatabaseFieldProtection";
     public const string DatabaseFieldProtectedPrefix = "P|";
+
+    /// <summary>
+    /// Default number of days an organization has to apply an updated license to their self-hosted installation after
+    /// their subscription has expired.
+    /// </summary>
+    public const int OrganizationSelfHostSubscriptionGracePeriodDays = 60;
 }
 
 public static class TokenPurposes

src/Core/Models/Business/OrganizationLicense.cs

@@ -78,7 +78,8 @@ public class OrganizationLicense : ILicense
                 subscriptionInfo.Subscription.PeriodDuration > TimeSpan.FromDays(180))
             {
                 Refresh = DateTime.UtcNow.AddDays(30);
-                Expires = subscriptionInfo?.Subscription.PeriodEndDate.Value.AddDays(60);
+                Expires = subscriptionInfo.Subscription.PeriodEndDate?.AddDays(Constants.OrganizationSelfHostSubscriptionGracePeriodDays);
+                ExpirationWithoutGracePeriod = subscriptionInfo.Subscription.PeriodEndDate;
             }
             else
             {
@@ -123,6 +124,7 @@ public class OrganizationLicense : ILicense
     public DateTime Issued { get; set; }
     public DateTime? Refresh { get; set; }
     public DateTime? Expires { get; set; }
+    public DateTime? ExpirationWithoutGracePeriod { get; set; }
     public bool Trial { get; set; }
     public LicenseType? LicenseType { get; set; }
     public string Hash { get; set; }
@@ -133,10 +135,12 @@ public class OrganizationLicense : ILicense
     /// <summary>
     /// Represents the current version of the license format. Should be updated whenever new fields are added.
     /// </summary>
-    private const int CURRENT_LICENSE_FILE_VERSION = 10;
+    /// <remarks>Intentionally set one version behind to allow self hosted users some time to update before
+    /// getting out of date license errors</remarks>
+    private const int CURRENT_LICENSE_FILE_VERSION = 11;
     private bool ValidLicenseVersion
     {
-        get => Version is >= 1 and <= 11;
+        get => Version is >= 1 and <= 12;
     }
 
     public byte[] GetDataBytes(bool forHash = false)
@@ -170,6 +174,8 @@ public class OrganizationLicense : ILicense
                     (Version >= 10 || !p.Name.Equals(nameof(UseScim))) &&
                     // UseCustomPermissions was added in Version 11
                     (Version >= 11 || !p.Name.Equals(nameof(UseCustomPermissions))) &&
+                    // ExpirationWithoutGracePeriod was added in Version 12
+                    (Version >= 12 || !p.Name.Equals(nameof(ExpirationWithoutGracePeriod))) &&
                     (
                         !forHash ||
                         (