strlen() was used in Phabricator to check if a generic value is a non-empty string.
This behavior is deprecated since PHP 8.1. So, we adopt an explicit cast to string
in order to answer the question "Is this a non-empty string?" without relying on implicit
cast and deprecated things.
Note: this may highlight other absurd input values that might be worth correcting
instead of just ignoring. If phutil_string_cast() throws an exception in your
instance, report it to Phorge to evaluate and fix that specific corner case.