Fix PHP 8.1 "strlen(null)" exception which blocks rendering the Home page

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 T15296

Test Plan: Applied this change and Home page rendered in web browser.

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: speck, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Maniphest Tasks: T15296

Differential Revision: https://we.phorge.it/D25145

src/applications/home/menuitem/PhabricatorHomeProfileMenuItem.php

@@ -26,7 +26,7 @@ final class PhabricatorHomeProfileMenuItem
     PhabricatorProfileMenuItemConfiguration $config) {
     $name = $config->getMenuItemProperty('name');
 
-    if (strlen($name)) {
+    if (phutil_nonempty_string($name)) {
       return $name;
     }