Fix EditProspectDialog and Prospects: prevent multiple modal openings during save and create operations

FoodsharingSiegen.Server/Pages/Prospects.razor.cs

@@ -56,13 +56,24 @@ namespace FoodsharingSiegen.Server.Pages
 
         #region Private Method CreateProspectAsync
 
+        private bool _isOpeningModal;
+
         /// <summary>
         ///     Asynchronously creates a new prospect by displaying the AddProspectModal dialog and refreshing the prospect list.
         /// </summary>
         /// <returns>A task that represents the asynchronous operation.</returns>
         private async Task CreateProspectAsync()
         {
-            await EditProspectDialog.ShowAsync(ModalService, LoadProspects);
+            if (_isOpeningModal) return;
+            _isOpeningModal = true;
+            try
+            {
+                await EditProspectDialog.ShowAsync(ModalService, LoadProspects);
+            }
+            finally
+            {
+                _isOpeningModal = false;
+            }
         }
 
         #endregion