[Fix] Reorder the enum to the correct order (#15540)

Co-authored-by: TJ Lambert <tjlambert@microsoft.com>

src/usernotifications.cs

@@ -171,10 +171,29 @@ namespace UserNotifications {
 	[Native]
 	public enum UNNotificationInterruptionLevel : long
 	{
-		Active,
-		Critical,
+#if XAMCORE_5_0
 		Passive,
+		Active,
 		TimeSensitive,
+		Critical,
+#else
+		[Obsolete ("Use 'Active2'.")]
+		Active,
+		[Obsolete ("Use 'Critical2'.")]
+		Critical,
+		[Obsolete ("Use 'Passive2'.")]
+		Passive,
+		[Obsolete ("Use 'TimeSensitive2'.")]
+		TimeSensitive,
+#endif // XAMCORE_5_0
+
+		// Additional enum values to fix reordering - to be at the end of the enum
+#if !XAMCORE_5_0
+		Active2 = Critical,
+		Critical2 = TimeSensitive,
+		Passive2 = Active,
+		TimeSensitive2 = Passive,
+#endif // !XAMCORE_5_0
 	}
 
 	[iOS (10, 0)]

tests/monotouch-test/UserNotifications/NotificationInterruptionLevel.cs

@@ -0,0 +1,32 @@
+using System;
+using NUnit.Framework;
+
+using Foundation;
+using UserNotifications;
+
+namespace MonoTouchFixtures.UserNotifications {
+
+	[TestFixture]
+	[Preserve (AllMembers = true)]
+	public class UNNotificationInterruptionLevelTest {
+
+		[Test]
+		public void EnumTest ()
+		{
+#if !XAMCORE_5_0
+			/* Apple Docs order these enum values as:
+			typedef NS_ENUM (NSUInteger, UNNotificationInterruptionLevel)
+			{
+				UNNotificationInterruptionLevelPassive,
+				UNNotificationInterruptionLevelActive,
+				UNNotificationInterruptionLevelTimeSensitive,
+				UNNotificationInterruptionLevelCritical,
+			} */
+			Assert.AreEqual ( (int)UNNotificationInterruptionLevel.Passive2, 0);
+			Assert.AreEqual ( (int)UNNotificationInterruptionLevel.Active2, 1);
+			Assert.AreEqual ( (int)UNNotificationInterruptionLevel.TimeSensitive2, 2);
+			Assert.AreEqual ( (int)UNNotificationInterruptionLevel.Critical2, 3);
+#endif
+		}
+	}
+}