fix(aws-mobile-client): Fixes passwordless auth (#2097)

Author: TrekSoft

aws-android-sdk-cognitoidentityprovider/src/main/java/com/amazonaws/mobileconnectors/cognitoidentityprovider/continuations/AuthenticationDetails.java

@@ -95,6 +95,7 @@ public AuthenticationDetails(String userId, Map<String, String> authenticationPa
         if (authenticationParameters != null) {
             this.authenticationType = CognitoServiceConstants.CHLG_TYPE_CUSTOM_CHALLENGE;
             this.authenticationParameters = authenticationParameters;
+            setAuthenticationParameter(CognitoServiceConstants.AUTH_PARAM_USERNAME, userId);
             setValidationData(validationData);
         } else {
             this.authenticationType = null;

aws-android-sdk-mobile-client/src/main/java/com/amazonaws/mobile/client/AWSMobileClient.java

@@ -1209,7 +1209,11 @@ public void getAuthenticationDetails(AuthenticationContinuation authenticationCo
                                             awsConfiguration.optJsonObject(AUTH_KEY).getString("authenticationFlowType").equals("CUSTOM_AUTH")
                                     ) {
                                         final HashMap<String, String> authParameters = new HashMap<String, String>();
-                                        authenticationContinuation.setAuthenticationDetails(new AuthenticationDetails(username, password, authParameters, validationData));
+                                        if (password != null) {
+                                            authenticationContinuation.setAuthenticationDetails(new AuthenticationDetails(username, password, authParameters, validationData));
+                                        } else {
+                                            authenticationContinuation.setAuthenticationDetails(new AuthenticationDetails(username, authParameters, validationData));
+                                        }
                                     } else {
                                         authenticationContinuation.setAuthenticationDetails(new AuthenticationDetails(username, password, validationData));
                                     }