[MessageUI] Fix enum sizes in .NET. (#13799)

src/MessageUI/MessageUI.cs

@@ -12,7 +12,7 @@ using ObjCRuntime;
 
 namespace MessageUI {
 
-#if XAMCORE_4_0
+#if NET
 	[Native]
 	public enum MFMailComposeResult : long {
 #else
@@ -27,7 +27,7 @@ namespace MessageUI {
 	}
 
 	[ErrorDomain ("MFMailComposeErrorDomain")]
-#if XAMCORE_4_0
+#if NET
 	[Native]
 	public enum MFMailComposeErrorCode : long {
 #else
@@ -39,7 +39,7 @@ namespace MessageUI {
 	    SendFailed
 	}
 
-#if XAMCORE_4_0
+#if NET
 	[Native]
 	public enum MessageComposeResult : long {
 #else

tests/xtro-sharpie/api-annotations-dotnet/iOS-MessageUI.ignore

@@ -1,7 +0,0 @@
-## [Native] available on XAMCORE_4_0
-!missing-enum-native! MessageComposeResult
-!missing-enum-native! MFMailComposeErrorCode
-!missing-enum-native! MFMailComposeResult
-!wrong-enum-size! MessageComposeResult managed 4 vs native 8
-!wrong-enum-size! MFMailComposeErrorCode managed 4 vs native 8
-!wrong-enum-size! MFMailComposeResult managed 4 vs native 8