Add data mappers for custom html block

[MAILPOET-2462]

assets/js/src/form_editor/store/blocks_to_form_body.jsx

@@ -83,6 +83,17 @@ export default (blocks) => {
           static: '0',
           params: '',
         };
+      case 'mailpoet-form/custom-html':
+        return {
+          ...mapped,
+          id: 'html',
+          type: 'html',
+          name: 'Custom text or HTML',
+          static: '0',
+          params: {
+            text: block.attributes && block.attributes.content ? block.attributes.content : '',
+          },
+        };
       default:
         return null;
     }

assets/js/src/form_editor/store/form_body_to_blocks.jsx

@@ -70,6 +70,15 @@ export default (data) => {
           name: 'mailpoet-form/divider',
           clientId: `divider_${index}`,
         };
+      case 'html':
+        return {
+          ...mapped,
+          name: 'mailpoet-form/custom-html',
+          clientId: `custom_html_${index}`,
+          attributes: {
+            content: item.params && item.params.text ? item.params.text : '',
+          },
+        };
       default:
         return null;
     }