Notifications: Review of PR to include path path #4629

- Merged book and chapter name items to a single page path list item
  which has links to parent page/chapter.
- Added permission filtering to page path elements.
- Added page path to also be on comment notifications.
- Updated testing to cover.
- Added new Message Line objects to support.

Done during review of #4629

app/Activity/Notifications/MessageParts/EntityPathMessageLine.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace BookStack\Activity\Notifications\MessageParts;
+
+use BookStack\Entities\Models\Entity;
+use Illuminate\Contracts\Support\Htmlable;
+use Stringable;
+
+/**
+ * A link to a specific entity in the system, with the text showing its name.
+ */
+class EntityPathMessageLine implements Htmlable, Stringable
+{
+    /**
+     * @var EntityLinkMessageLine[]
+     */
+    protected array $entityLinks;
+
+    public function __construct(
+        protected array $entities
+    ) {
+        $this->entityLinks = array_map(fn (Entity $entity) => new EntityLinkMessageLine($entity, 24), $this->entities);
+    }
+
+    public function toHtml(): string
+    {
+        $entityHtmls = array_map(fn (EntityLinkMessageLine $line) => $line->toHtml(), $this->entityLinks);
+        return implode(' &gt; ', $entityHtmls);
+    }
+
+    public function __toString(): string
+    {
+        return implode(' > ', $this->entityLinks);
+    }
+}