Fix PHP 8.1 "strlen(null)" exception which blocks rendering the Projects page (and log alien values)

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 general replacement.

In this specific case we use phutil_nonempty_stringlike() since we are not sure
if the variable href should be just a string or other objects.

In order not to leave these cases to chance, we have added a log line, which can be
removed in the future.

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 T15303
Ref T15316

Test Plan:
Applied this change (on top of D25144, D25145, D25146, D25147, D25150,
D25142) and /project/ rendered in web browser.

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

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

Maniphest Tasks: T15303, T15316

Differential Revision: https://we.phorge.it/D25153