The array_map was only ran on small parts of the actual error array instead
of the whole one. This resulted in the output of the language variables' names
rather than their actual value.
PHPBB3-11548
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
The input length for the hex color is now limited to 6 characters and
the support for colors starting with a '#' has been dropped. The allowed
input length of 7 in prosilver seems to have been a relict from old ages
of phpBB3. In order to have proper support for correct checking of the
colour value, the new code was also ported to the ACP groups manage page.
The tests have been modified to reflect the changes to the behavior of
the color check. Tests for the ACP will follow.
PHPBB3-11538
We are now using a regex with preg_match() in order to properly check
if the entered color value is in hex color format or not. A proper
error message is triggered if an incorrect color value is entered and
the prepended '#' is removed if necessary.
PHPBB3-11538
