[Tests] Make test inconclusive if httpbin does not return the headers. (

#5684)

In some cases, httpbin might return errors or other results. In that
case, we cannot assert that the auth headers are not present. We set the
test to inconclusive to ensure that we do not fail due to the external
page.

Fixes xamarin/maccore#1453

tests/monotouch-test/System.Net.Http/MessageHandlers.cs

@@ -152,8 +152,9 @@ public void RedirectionWithAuthorizationHeaders (Type handlerType)
 
 			if (!done) { // timeouts happen in the bost due to dns issues, connection issues etc.. we do not want to fail
 				Assert.Inconclusive ("Request timedout.");
+			} else if (!containsHeaders) {
+				Assert.Inconclusive ("Response from httpbin does not contain headers, therefore we cannot ensure that if the authoriation is present.");
 			} else {
-				Assert.IsTrue (containsHeaders, "Request did not reach final destination.");
 				Assert.IsFalse (containsAuthorizarion, $"Authorization header did reach the final destination. {json}");
 				Assert.IsNull (ex, $"Exception {ex} for {json}");
 			}