[ticket/11339] Always clear timeout functions on subsequent AJAX calls

PHPBB3-11339
Merge remote-tracking branch 'remotes/prototech/ticket/11339' into develop-ascraeus

# By Cesar G
# Via Cesar G
* remotes/prototech/ticket/11339:
  [ticket/11339] Always clear timeout functions on subsequent AJAX calls
Merge branch 'develop-ascraeus' into develop

# By Cesar G
# Via Cesar G (1) and Nathaniel Guse (1)
* develop-ascraeus:
  [ticket/11339] Always clear timeout functions on subsequent AJAX calls