Use minor usints converter service instead of toMinorUnits function.

Closes #3507218

src/Plugin/Commerce/PaymentGateway/DatatransBase.php

@@ -288,7 +288,7 @@ class DatatransBase extends PaymentGatewayBase implements SupportsRefundsInterfa
     $this->assertRefundAmount($payment, $amount);
 
     $data = [
-      'amount' => $this->toMinorUnits($amount),
+      'amount' => $this->minorUnitsConverter->toMinorUnits($amount),
       'currency' => $amount->getCurrencyCode(),
       'refno' => $payment->getOrderId(),
     ];
@@ -348,7 +348,7 @@ class DatatransBase extends PaymentGatewayBase implements SupportsRefundsInterfa
     $order = $payment->getOrder();
 
     // Calculate the amount in the form Datatrans expects it.
-    $amount = $this->toMinorUnits($payment->getAmount());
+    $amount = $this->minorUnitsConverter->toMinorUnits($payment->getAmount());
 
     $data = NestedArray::mergeDeep($data, [
       'currency' => $payment->getAmount()->getCurrencyCode(),
@@ -416,7 +416,7 @@ class DatatransBase extends PaymentGatewayBase implements SupportsRefundsInterfa
     $order = $payment->getOrder();
 
     // Calculate the amount in the form Datatrans expects it.
-    $amount = $this->toMinorUnits($payment->getAmount());
+    $amount = $this->minorUnitsConverter->toMinorUnits($payment->getAmount());
 
     $data = NestedArray::mergeDeep($data, [
       'currency' => $payment->getAmount()->getCurrencyCode(),