Summary: `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 phutil_nonempty_string() throws an exception in your instance, report it to Phorge to evaluate and fix that specific corner case. Closes T15300 Test Plan: Applied these three changes (on top of D25144, D25145, D25146, D25147) and `/diffusion/` finally rendered in web browser. Reviewers: O1 Blessed Committers, avivey Reviewed By: O1 Blessed Committers, avivey Subscribers: speck, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno Maniphest Tasks: T15300 Differential Revision: https://we.phorge.it/D25150