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.
Similarly, `preg_match()` does not accept passing `null` as `$subject` parameter since PHP 8.1.
Closes T15381
Test Plan: Applied these two changes (on top of D25179 and D25213), and on the task creation page, after clicking the magnifier icon in the "Subscribers" field, the "Browse Subscribers" overlay dialog got rendered.
Reviewers: O1 Blessed Committers, valerio.bozzolan
Reviewed By: O1 Blessed Committers, valerio.bozzolan
Subscribers: speck, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno
Maniphest Tasks: T15381
Differential Revision: https://we.phorge.it/D25214
3a3112f67b