[ticket/12334] Add PROFILE_FIELD_VALUE_RAW template var

Completed original PR #2218 by @PayBas, add unit tests within the new CPF unit tests

[PHPBB3-12334](https://tracker.phpbb.com/browse/PHPBB3-12334)
should be $field_value can be string `0`?
This looks like a bug we should adresse in the future