Need to cache locationmanager or dialog dissapears (#1072)

Author: jamesmontemagno

Xamarin.Essentials/Permissions/Permissions.ios.tvos.watchos.cs

@@ -125,9 +125,11 @@ internal static PermissionStatus GetLocationStatus(bool whenInUse)
                 };
             }
 
+            static CLLocationManager locationManager;
+
             internal static Task<PermissionStatus> RequestLocationAsync(bool whenInUse, Action<CLLocationManager> invokeRequest)
             {
-                var locationManager = new CLLocationManager();
+                locationManager = new CLLocationManager();
 
                 var tcs = new TaskCompletionSource<PermissionStatus>(locationManager);
 
@@ -155,6 +157,8 @@ void LocationAuthCallback(object sender, CLAuthorizationChangedEventArgs e)
                                 {
                                     locationManager.AuthorizationChanged -= LocationAuthCallback;
                                     tcs.TrySetResult(GetLocationStatus(whenInUse));
+                                    locationManager.Dispose();
+                                    locationManager = null;
                                 }
                             });
                             return;
@@ -164,6 +168,8 @@ void LocationAuthCallback(object sender, CLAuthorizationChangedEventArgs e)
                     locationManager.AuthorizationChanged -= LocationAuthCallback;
 
                     tcs.TrySetResult(GetLocationStatus(whenInUse));
+                    locationManager.Dispose();
+                    locationManager = null;
                 }
             }
         }