captive portal, increase timeout, sometimes 2 seconds may not be enough.

fix for:
PHP Warning:  SQLite3Stmt::execute(): Unable to execute statement: database is locked in /usr/local/opnsense/scripts/OPNsense/CaptivePortal/process_accounting_messages.php on line 68

(cherry picked from commit 3f4d694f)

src/opnsense/scripts/OPNsense/CaptivePortal/process_accounting_messages.php

@@ -35,7 +35,7 @@ use OPNsense\Auth\AuthenticationFactory;
 // open database
 $database_filename = '/var/captiveportal/captiveportal.sqlite';
 $db = new SQLite3($database_filename);
-$db->busyTimeout(2000);
+$db->busyTimeout(20000);
 
 // query all sessions with client restrictions
 $result = $db->query('