FIX: Focus first button in topic admin menu (PR #10562)

Peek 2020-08-31 15-43

When using Shift+A to toggle the admin menu for a topic the first button was not focused, so the menu could not be navigated with tab.

GitHub

Instead of next() you can take advantage of the recently added callback - didRenderWidget! :smiley: For example see:

https://github.com/discourse/discourse/pull/10496/files#diff-796ca2d406c1ba53a991622c8b6c2e3cR245