[ticket/11754] Remove styleswitcher leftovers

PHPBB3-11754
[ticket/11784] Remove naming redundancy for event listeners

PHPBB3-11784
Merge remote-tracking branch 'VSEphpbb/ticket/11784' into develop

# By Matt Friedman
# Via Matt Friedman
* VSEphpbb/ticket/11784:
  [ticket/11784] Remove naming redundancy for event listeners
Merge remote-tracking branch 'cyberalien/ticket/11754' into develop

* cyberalien/ticket/11754:
  [ticket/11754] Remove styleswitcher leftovers