Updated guest settings system to format value as per non-guest

Fixes #1431

app/Settings/SettingService.php

@@ -4,10 +4,8 @@ use Illuminate\Contracts\Cache\Repository as Cache;
 
 /**
  * Class SettingService
- *
  * The settings are a simple key-value database store.
- *
+ * For non-authenticated users, user settings are stored via the session instead.
- * @package BookStack\Services
  */
 class SettingService
 {
@@ -52,6 +50,19 @@ class SettingService
         return $formatted;
     }
 
+    /**
+     * Get a value from the session instead of the main store option.
+     * @param $key
+     * @param bool $default
+     * @return mixed
+     */
+    protected function getFromSession($key, $default = false)
+    {
+        $value = session()->get($key, $default);
+        $formatted = $this->formatValue($value, $default);
+        return $formatted;
+    }
+
     /**
      * Get a user-specific setting from the database or cache.
      * @param \BookStack\Auth\User $user
@@ -62,7 +73,7 @@ class SettingService
     public function getUser($user, $key, $default = false)
     {
         if ($user->isDefault()) {
-            return session()->get($key, $default);
+            return $this->getFromSession($key, $default);
         }
         return $this->get($this->userKey($user->id, $key), $default);
     }