BREAKING CHANGE: updated description of AuthenticationException in case of empty description (#756)

Author: desusai7

auth0/src/main/java/com/auth0/android/authentication/AuthenticationException.kt

@@ -86,7 +86,7 @@ public class AuthenticationException : Auth0Exception {
         if (!TextUtils.isEmpty(description)) {
             return description!!
         }
-        return if (UNKNOWN_ERROR == getCode()) {
+        return if (UNKNOWN_ERROR != getCode()) {
             String.format("Received error with code %s", getCode())
         } else "Failed with unknown error"
     }

auth0/src/test/java/com/auth0/android/authentication/AuthenticationExceptionTest.kt

@@ -134,8 +134,7 @@ public class AuthenticationExceptionTest {
             CoreMatchers.`is`(
                 CoreMatchers.equalTo(
                     String.format(
-                        "Received error with code %s",
-                        Auth0Exception.UNKNOWN_ERROR
+                        "Failed with unknown error"
                     )
                 )
             )
@@ -150,7 +149,7 @@ public class AuthenticationExceptionTest {
         )
         MatcherAssert.assertThat(
             ex.getDescription(),
-            CoreMatchers.`is`(CoreMatchers.equalTo("Failed with unknown error"))
+            CoreMatchers.`is`(CoreMatchers.equalTo("Received error with code a_valid_code"))
         )
     }