alerts not shown when app in foreground (#646)

## Summary
When the device receives a remote notification to display an alert,
either
a) the app is not in the foreground and the alert is shown in the
Notification Center or
b) the app is in the foreground and thus far no alert was shown at all -
neither in the app nor in iOS's Notification Center.


*For UI changes including screenshots of before and after is great.*

## Validation
Dropped a particularly formatted .apns json file onto the simulator.


Perhaps this fixes #460.

Author: krugerk

BeeSwift/AppDelegate.swift

@@ -17,7 +17,7 @@ import AlamofireNetworkActivityIndicator
 import BeeKit
 
 @UIApplicationMain
-class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate {
+class AppDelegate: UIResponder, UIApplicationDelegate {
     let logger = Logger(subsystem: "com.beeminder.beeminder", category: "AppDelegate")
     let backgroundUpdates = BackgroundUpdates()
 
@@ -41,6 +41,8 @@ class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterD
 
         NetworkActivityIndicatorManager.shared.isEnabled = true
 
+        UNUserNotificationCenter.current().delegate = self
+        
         NotificationCenter.default.addObserver(self, selector: #selector(self.handleGoalsUpdated), name: GoalManager.NotificationName.goalsUpdated, object: nil)
         NotificationCenter.default.addObserver(self, selector: #selector(self.handleUserSignedOut), name: CurrentUserManager.NotificationName.signedOut, object: nil)
 
@@ -161,12 +163,6 @@ class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterD
         }
     }
 
-    // MARK: - UNUserNotificationCenterDelegate
-    
-    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
-        completionHandler([.list, .banner, .sound, .badge])
-    }
-    
     private func resetStateIfUITesting() {
         if ProcessInfo.processInfo.arguments.contains("UI-Testing") {
             UserDefaults.standard.removePersistentDomain(forName: Bundle.main.bundleIdentifier!)
@@ -177,3 +173,12 @@ class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterD
         UNUserNotificationCenter.current().removeAllPendingNotificationRequests()
     }
 }
+
+// MARK: - UNUserNotificationCenterDelegate
+
+extension AppDelegate: UNUserNotificationCenterDelegate {
+    func userNotificationCenter(_ center: UNUserNotificationCenter,
+                                willPresent notification: UNNotification) async -> UNNotificationPresentationOptions {
+        [.list, .banner, .sound, .badge]
+    }
+}