MDL-49795 tool_privacy: Add missing metadata providers for purpose table

admin/tool/dataprivacy/classes/privacy/provider.php

@@ -79,6 +79,16 @@ public static function get_metadata(collection $collection) : collection {
             'privacy:metadata:request'
         );
 
+        // Regarding this block, we are unable to export or purge this data, as
+        // it would damage the privacy data across the whole site.
+        $collection->add_database_table(
+            'tool_dataprivacy_purposerole',
+            [
+                'usermodified' => 'privacy:metadata:purpose:usermodified',
+            ],
+            'privacy:metadata:purpose'
+        );
+
         $collection->add_user_preference(tool_helper::PREF_REQUEST_FILTERS,
             'privacy:metadata:preference:tool_dataprivacy_request-filters');
         $collection->add_user_preference(tool_helper::PREF_REQUEST_PERPAGE,

admin/tool/dataprivacy/lang/en/tool_dataprivacy.php

@@ -232,6 +232,8 @@
 $string['privacyofficeronly'] = 'Only users who are assigned a privacy officer role ({$a}) have access to this content';
 $string['privacy:metadata:preference:tool_dataprivacy_request-filters'] = 'The filters currently applied to the data requests page.';
 $string['privacy:metadata:preference:tool_dataprivacy_request-perpage'] = 'The number of data requests the user prefers to see on one page';
+$string['privacy:metadata:purpose'] = 'Information from data purposes made for this site.';
+$string['privacy:metadata:purpose:usermodified'] = 'The ID of the user to who modified the purpose';
 $string['privacy:metadata:request'] = 'Information from personal data requests (subject access and deletion requests) made for this site.';
 $string['privacy:metadata:request:comments'] = 'Any user comments accompanying the request.';
 $string['privacy:metadata:request:userid'] = 'The ID of the user to whom the request belongs';