Fix wrong behavior when an update is canceled during download & multiple check errors in some cases

Core/FormBrowser.cs

@@ -250,11 +250,11 @@ private void updates_CheckFinished(object sender, UpdateCheckEventArgs e){
                 }, ex => {
                     if (!ignoreUpdateCheckError){
                         Program.Reporter.HandleException("Update Check Error", "An error occurred while checking for updates.", true, ex);
-
-                        ignoreUpdateCheckError = true;
                         updates.StartTimer();
                     }
                 });
+                
+                ignoreUpdateCheckError = true;
             });
         }
 
@@ -274,7 +274,7 @@ private void updates_UpdateAccepted(object sender, UpdateEventArgs e){
                         UpdateInstallerPath = update.InstallerPath;
                         ForceClose();
                     }
-                    else if (FormMessage.Error("Update Has Failed", "Could not automatically download the update: "+(update.DownloadError?.Message ?? "unknown error")+"\n\nWould you like to open the website and try downloading the update manually?", FormMessage.Yes, FormMessage.No)){
+                    else if (status != UpdateDownloadStatus.Canceled && FormMessage.Error("Update Has Failed", "Could not automatically download the update: "+(update.DownloadError?.Message ?? "unknown error")+"\n\nWould you like to open the website and try downloading the update manually?", FormMessage.Yes, FormMessage.No)){
                         BrowserUtils.OpenExternalBrowser(Program.Website);
                         ForceClose();
                     }

Updates/FormUpdateDownload.cs

@@ -22,6 +22,7 @@ private void btnCancel_Click(object sender, EventArgs e){
         private void timerDownloadCheck_Tick(object sender, EventArgs e){
             if (updateInfo.DownloadStatus.IsFinished()){
                 timerDownloadCheck.Stop();
+                DialogResult = DialogResult.OK;
                 Close();
             }
         }

Updates/UpdateDownloadStatus.cs

@@ -2,9 +2,10 @@
     public enum UpdateDownloadStatus{
         None = 0,
         InProgress,
+        Canceled,
         AssetMissing,
-        Done,
+        Failed,
-        Failed
+        Done
     }
 
     public static class UpdateDownloadStatusExtensions{

Updates/UpdateHandler.cs

@@ -101,6 +101,10 @@ public void BeginUpdateDownload(Form ownerForm, UpdateInfo updateInfo, Action<Up
                 };
 
                 downloadForm.FormClosed += (sender, args) => {
+                    if (downloadForm.DialogResult != DialogResult.OK){
+                        updateInfo.CancelDownload();
+                    }
+
                     downloadForm.Dispose();
                     onFinished(updateInfo);
                 };

Updates/UpdateInfo.cs

@@ -72,6 +72,11 @@ public void DeleteInstaller(){
             }
         }
 
+        public void CancelDownload(){
+            DeleteInstaller();
+            DownloadStatus = UpdateDownloadStatus.Canceled;
+        }
+
         public override bool Equals(object obj){
             return obj is UpdateInfo info && VersionTag == info.VersionTag;
         }