PHPStan: Remove ignored error that is no longer needed.

Author: JJJ

phpstan.neon.dist

@@ -15,7 +15,6 @@ parameters:
         # WP_CLI\Fetchers\User::get() returns WP_User without root namespace.
         - '/^Cannot access property \$ID on WP_CLI\\Fetchers\\WP_User\|false\.$/'
         # Backward compatibility with old method of passing arguments.
-        - '/^Call to function is_array\(\) with array<string, mixed> will always evaluate to true\.$/'
         # Associative CLI arguments. Passed by reference.
         - '/^Parameter \&\$assoc_args by-ref type of method WP_MS_Network_Command::get_formatter\(\) expects array<string, mixed>, array given\.$/'