Revert so-widgets-bundle to 1.17.8

Author: jlyon

composer.json

@@ -300,7 +300,7 @@
 
         "wpackagist-plugin/classic-editor": "1.6",
         "wpackagist-plugin/siteorigin-panels": "2.11.5",
-        "wpackagist-plugin/so-widgets-bundle": "1.17.9",
+        "wpackagist-plugin/so-widgets-bundle": "1.17.8",
 
         "wpackagist-plugin/wordpress-faq-manager": "1.331",
         "wpackagist-plugin/events-manager":  "5.9.8.1",