Merged PR 57147: Add @api annotation to Log Viewer layout

## What's being changed

The LogViewer block.

## Why it's being changed

Magento static tests decree that any block referenced in a public layout XML file must be marked with the `@api` annotation.

## How to review / test this change

- Don't see errors relating to this block appear in static tests

Related work items: #267336

Block/Adminhtml/LogViewer.php

@@ -2,9 +2,11 @@
 
 namespace Dotdigitalgroup\Email\Block\Adminhtml;
 
+/**
+ * @api
+ */
 class LogViewer extends \Magento\Backend\Block\Widget\Container
 {
-
     /**
      * @var string
      */