[create_timepoint] Fix type errors in timepoint creation (aces#9361)

LorisForm returns values as strings, but \ProjectID::singleton and
\CenterID::singleton take integer values. This updates the singleton
calls to cast as an int to fix the type errors on timepoint creation.

Fixes aces#9357

modules/create_timepoint/php/timepoint.class.inc

@@ -151,7 +151,7 @@ class Timepoint extends \NDB_Page implements ETagCalculator
         if ($num_sites == 1) {
             $site = \Site::singleton($user_list_of_sites[0]);
         } else if ($num_sites > 1) {
-            $site = \Site::singleton(\CenterID::singleton(($values['psc'])));
+            $site = \Site::singleton(\CenterID::singleton((intval($values['psc']))));
         }
 
         // Project
@@ -161,7 +161,7 @@ class Timepoint extends \NDB_Page implements ETagCalculator
             // if there is only one project, autoselect first project from array of 1
             $project = \Project::getProjectFromID(array_pop($user_list_of_projects));
         } else if (count($user_list_of_projects) > 1) {
-            $project_id = \ProjectID::singleton($values['project']);
+            $project_id = \ProjectID::singleton(intval($values['project']));
             $project    = \Project::getProjectFromID($project_id);
         }
 
@@ -234,7 +234,9 @@ class Timepoint extends \NDB_Page implements ETagCalculator
             null : $values['psc'];
 
         // validate site entered
-        $site = !empty($values['psc']) ? \CenterID::singleton($values['psc']) : null;
+        $site = !empty($values['psc'])
+            ?  \CenterID::singleton(intval($values['psc']))
+            : null;
 
         $user_list_of_sites = $user->getCenterIDs();
         $num_sites          = count($user_list_of_sites);
@@ -261,7 +263,7 @@ class Timepoint extends \NDB_Page implements ETagCalculator
 
         $candid    = $values['candID'];
         $cohortID  = intval($values['cohort']);
-        $projectID = \ProjectID::singleton($values['project']);
+        $projectID = \ProjectID::singleton(intval($values['project']));
 
         //Visit - Get all visits to map ID back to label for session table
         $visits     = \Utility::getVisitsForProjectCohort(