Change Active Storage destroy callbacks

There is concern that only blob are deleted depending on
the `before_destroy` definition order which throws abort.

activestorage/CHANGELOG.md

+*   Use `after_destroy_commit` instead of `before_destroy` for purging
+    attachments when a record is destroyed.
+
+    *Hiroki Zenigami*
+
+
 *   Force `:attachment` disposition for specific, configurable content types.
     This mitigates possible security issues such as XSS or phishing when
     serving them inline. A list of such content types is included by default,

activestorage/lib/active_storage/attached/macros.rb

@@ -44,7 +44,7 @@ def #{name}=(attachable)
       scope :"with_attached_#{name}", -> { includes("#{name}_attachment": :blob) }
 
       if dependent == :purge_later
-        before_destroy { public_send(name).purge_later }
+        after_destroy_commit { public_send(name).purge_later }
       end
     end
 
@@ -89,7 +89,7 @@ def #{name}=(attachables)
       scope :"with_attached_#{name}", -> { includes("#{name}_attachments": :blob) }
 
       if dependent == :purge_later
-        before_destroy { public_send(name).purge_later }
+        after_destroy_commit { public_send(name).purge_later }
       end
     end
   end