[ticket/11548] Run array_map on complete error array and not just colour_error

Up to now the array_map() that turns error messages into the localized output
was only ran if the group's color was set. With this patch it'll run the
array_map() on the complete error array if it's not empty.

PHPBB3-11548
Merge branch 'develop-olympus' of https://github.com/phpbb/phpbb3 into ticket/11548
[ticket/11548] Use new static methods for request and submit

PHPBB3-11548
Merge remote-tracking branch 'marc1706/ticket/11548' into develop-olympus

* marc1706/ticket/11548:
  [ticket/11548] Use new static methods for request and submit
  [ticket/11548] Run array_map on complete error array and not just colour_error