Add form block wrapper renderer

[MAILPOET-2746]

lib/Form/BlockWrapperRenderer.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace MailPoet\Form;
+
+use MailPoet\Models\Form;
+
+class BlockWrapperRenderer {
+  public function render(array $block, string $blockContent): string {
+    return '<div class="mailpoet_paragraph">' . $blockContent . '</div>';
+  }
+}