`strlen()` was used in Phabricator to check if a generic value is a non-empty string.
This behavior is deprecated since PHP 8.1. Phorge adopts `phutil_nonempty_string()` as a replacement.
Note: this may highlight other absurd input values that might be worth correcting
instead of just ignoring. If your phutil_nonempty_string() throws an exception, just
report it to Phorge to evaluate and fix together that specific corner case.
Closes T15286