fix(auth): Fix HostedUI signout cancellation issue (#2834)

Author: tylerjroach

aws-auth-cognito/src/main/java/com/amplifyframework/auth/cognito/RealAWSCognitoAuthPlugin.kt

@@ -1880,6 +1880,7 @@ internal class RealAWSCognitoAuthPlugin(
 
     private fun _signOut(sendHubEvent: Boolean = true, onComplete: Consumer<AuthSignOutResult>) {
         val token = StateChangeListenerToken()
+        var cancellationException: UserCancelledException? = null
         authStateMachine.listen(
             token,
             { authState ->
@@ -1921,6 +1922,18 @@ internal class RealAWSCognitoAuthPlugin(
                                 )
                             )
                         }
+                        authNState is AuthenticationState.SigningOut -> {
+                            val state = authNState.signOutState
+                            if (state is SignOutState.Error && state.exception is UserCancelledException) {
+                                cancellationException = state.exception
+                            }
+                        }
+                        authNState is AuthenticationState.SignedIn && cancellationException != null -> {
+                            authStateMachine.cancel(token)
+                            cancellationException?.let {
+                                onComplete.accept(AWSCognitoAuthSignOutResult.FailedSignOut(it))
+                            }
+                        }
                         else -> {
                             // No - op
                         }

aws-auth-cognito/src/main/java/com/amplifyframework/statemachine/codegen/states/SignOutState.kt

@@ -15,6 +15,7 @@
 
 package com.amplifyframework.statemachine.codegen.states
 
+import com.amplifyframework.auth.cognito.exceptions.service.UserCancelledException
 import com.amplifyframework.auth.cognito.isAuthEvent
 import com.amplifyframework.auth.cognito.isSignOutEvent
 import com.amplifyframework.statemachine.State
@@ -86,7 +87,15 @@ internal sealed class SignOutState : State {
                     }
                     is SignOutEvent.EventType.UserCancelled -> {
                         val action = signOutActions.userCancelledAction(signOutEvent)
-                        StateResolution(Error(Exception("User Cancelled")), listOf(action))
+                        StateResolution(
+                            Error(
+                                UserCancelledException(
+                                    "The user cancelled the sign-out attempt, so it did not complete.",
+                                    "To recover: catch this error, and attempt the sign out again."
+                                )
+                            ),
+                            listOf(action)
+                        )
                     }
                     else -> defaultResolution
                 }