[ticket/11581] Add assertNotContainsLang function to function test framework

PHPBB3-11581
[ticket/11581] Add test to check UCP_PM is enabled/disabled correctly

PHPBB3-11581
[ticket/11581] Enabled private messages after tests

PHPBB3-11581
[ticket/11581] Fix year in copyright header

PHPBB3-11581
[ticket/11581] Add module_auth to UCP_PM module

module_auth = cfg_allow_privmsg in UCP_PM module so that the Private
Messages tab is not displayed when this config value is false.

PHPBB3-11581
[ticket/11581] Update module_auth for UCP_PM in migration

PHPBB3-11581
[ticket/11581] Fix spacing in function docblock

PHPBB3-11581
[ticket/11581] Add $module_auth === false condition to effective install

PHPBB3-11581