Remove unused paymentPhase parameter from multi-payment initialization

Author: tuncaserhat

samples/init_multi_payment.php

@@ -15,7 +15,6 @@
     'conversationId' => '456d1297-908e-4bd6-a13b-4be31a6e47d5',
     'externalId' => Guid::generate(),
     'paymentGroup' => PaymentGroup::PRODUCT,
-    'paymentPhase' => PaymentPhase::AUTH,
     'items' => array(
         array(
             'name' => 'Item 1',