Refactor interaction and user deletion logic

Consolidated repeated methods for interaction/user deletion into reusable components to improve maintainability. Introduced a `ConfirmDialog` for consistent confirmation UI and streamlined associated logic across pages. Removed redundant methods and enhanced admin-specific page security checks.

FoodsharingSiegen.Server/Pages/ProspectsDone.razor.cs

@@ -56,31 +56,5 @@ namespace FoodsharingSiegen.Server.Pages
         }
 
         #endregion
-
-        #region Private Method RemoveInteraction
-
-        /// <summary>
-        ///     Removes the interaction using the specified arg (a. beging, 11.04.2022)
-        /// </summary>
-        /// <param name="arg">The arg</param>
-        private async Task RemoveInteraction(Guid arg)
-        {
-            var confirm = await Message.Confirm("Interaktion wirklich löschen?", "Bestätigen", o =>
-            {
-                o.ConfirmButtonText = "Ja, wirklich!";
-                o.CancelButtonText = "Abbrechen";
-                o.ShowMessageIcon = false;
-            });
-
-            if (confirm)
-            {
-                await ProspectService.RemoveInteraction(arg);
-                await LoadProspects();
-            }
-
-            await InvokeAsync(StateHasChanged);
-        }
-
-        #endregion
     }
 }