MDL-71107 core_contentbank: Fill content author when copying a course

'usercreated' and 'usermodified' fields can not be always mapped.
We are filling those fields with 'old' users when working on the same
site, or with current user when working on a different instance.

backup/moodle2/restore_stepslib.php

@@ -4065,9 +4065,30 @@ public function process_contentbankcontent($data) {
         $exists = $DB->record_exists('contentbank_content', $params);
         if (!$exists) {
             $params['configdata'] = $data->configdata;
+            $params['timemodified'] = time();
+
+            // Trying to map users. Users cannot always be mapped, e.g. when copying.
             $params['usercreated'] = $this->get_mappingid('user', $data->usercreated);
+            if (!$params['usercreated']) {
+                // Leave the content creator unchanged when we are restoring the same site.
+                // Otherwise use current user id.
+                if ($this->task->is_samesite()) {
+                    $params['usercreated'] = $data->usercreated;
+                } else {
+                    $params['usercreated'] = $this->task->get_userid();
+                }
+            }
             $params['usermodified'] = $this->get_mappingid('user', $data->usermodified);
-            $params['timemodified'] = time();
+            if (!$params['usermodified']) {
+                // Leave the content modifier unchanged when we are restoring the same site.
+                // Otherwise use current user id.
+                if ($this->task->is_samesite()) {
+                    $params['usermodified'] = $data->usermodified;
+                } else {
+                    $params['usermodified'] = $this->task->get_userid();
+                }
+            }
+
             $newitemid = $DB->insert_record('contentbank_content', $params);
             $this->set_mapping('contentbank_content', $oldid, $newitemid, true);
         }