string false does not evaluate to false

The false value used here https://github.com/magento/magento2/blob/develop/app/code/Magento/Sales/etc/pdf.xml#L33 gets represented as a string which leads to all totals being shown in the pdfs even if the amount is 0 and it is configured to not show. Checking for the string true fixes it.

app/code/Magento/Sales/Model/Order/Pdf/Total/DefaultTotal.php

@@ -145,7 +145,7 @@ public function getFullTaxInfo()
     public function canDisplay()
     {
         $amount = $this->getAmount();
-        return $this->getDisplayZero() || $amount != 0;
+        return $this->getDisplayZero() === 'true' || $amount != 0;
     }
 
     /**