Merge forwardport of #11297 to 2.3-develop branch

Applied pull request patch https://github.com/magento/magento2/pull/11297.patch (created by @michielgerritsen) based on commit(s):
  1. 60d6628

Fixed GitHub Issues in 2.3-develop branch:
  - #5105: Error While send Invoice with Grouped Products (reported by @srbarba)

app/code/Magento/Sales/view/frontend/templates/email/items/invoice/default.phtml

@@ -31,6 +31,6 @@
     </td>
     <td class="item-qty"><?= /* @escapeNotVerified */  $_item->getQty() * 1 ?></td>
     <td class="item-price">
-        <?= /* @escapeNotVerified */  $block->getItemPrice($_item) ?>
+        <?= /* @escapeNotVerified */  $block->getItemPrice($_item->getOrderItem()) ?>
     </td>
 </tr>