remove duplicated currency_code

Author: Bashev

app/code/Magento/GoogleGtag/Block/Ga.php

@@ -152,13 +152,12 @@ public function getOrdersTrackingData(): array
                     'affiliation' => $this->_escaper->escapeHtml(
                         $this->_storeManager->getStore()->getFrontendName()
                     ),
-                    'price' => number_format((float) $item->getPrice(), 2),
+                    'price' => round((float) $item->getPrice(), 2),
                     'quantity' => (int)$item->getQtyOrdered()
                 ];
             }
             $result['orders'][] = [
                 'transaction_id' =>  $order->getIncrementId(),
-                'currency' =>  $order->getOrderCurrencyCode(),
                 'value' => round((float) $order->getGrandTotal(), 2),
                 'tax' => round((float) $order->getTaxAmount(), 2),
                 'shipping' => round((float) $order->getShippingAmount(), 2),

app/code/Magento/GoogleGtag/Test/Unit/Block/GaTest.php

@@ -171,7 +171,6 @@ public function testOrderTrackingData()
             'orders' => [
                 [
                     'transaction_id' => 100,
-                    'currency' => 'USD',
                     'value' => 10.00,
                     'tax' => 2.00,
                     'shipping' => 1.00,