MDL-85036 completion: Properly initialize cm_info for user completion

public/completion/classes/external/completion_info_exporter.php

@@ -53,7 +53,7 @@ class completion_info_exporter extends \core\external\exporter {
      */
     public function __construct(object $course, object $cm, int $userid, array $related = []) {
         $this->course = $course;
-        $this->cminfo = \cm_info::create($cm);
+        $this->cminfo = \cm_info::create($cm, $userid);
         $this->userid = $userid;
         parent::__construct([], $related);
     }

public/course/classes/cm_info.php

@@ -1412,8 +1412,8 @@ class cm_info implements IteratorAggregate {
         if (!$cm) {
             return null;
         }
-        // If it is already a cm_info object, just return it.
-        if ($cm instanceof cm_info) {
+        // If it is already a cm_info object with the right user, just return it.
+        if (($cm instanceof cm_info) && ($cm->get_modinfo()->userid == $userid)) {
             return $cm;
         }
         // Otherwise load modinfo.