Only updates ALTAppID features when they have changed

AltStore/Operations/ResignAppOperation.swift

@@ -264,6 +264,27 @@ private extension ResignAppOperation
             features[.appGroups] = true
         }
         
+        var updateFeatures = false
+        
+        // Determine whether the required features are already enabled for the AppID.
+        for (feature, value) in features
+        {
+            if let appIDValue = appID.features[feature] as AnyObject?, (value as AnyObject).isEqual(appIDValue)
+            {
+                // AppID already has this feature enabled and the values are the same.
+                continue
+            }
+            else
+            {
+                // AppID either doesn't have this feature enabled or the value has changed,
+                // so we need to update it to reflect new values.
+                updateFeatures = true
+                break
+            }
+        }
+        
+        if updateFeatures
+        {
             let appID = appID.copy() as! ALTAppID
             appID.features = features
             
@@ -271,6 +292,11 @@ private extension ResignAppOperation
                 completionHandler(Result(appID, error))
             }
         }
+        else
+        {
+            completionHandler(.success(appID))
+        }
+    }
     
     func updateAppGroups(for appID: ALTAppID, app: ALTApplication, team: ALTTeam, session: ALTAppleAPISession, completionHandler: @escaping (Result<ALTAppID, Error>) -> Void)
     {