MDL-68894 user: Wrap bottom enrol buttons like top

The div wrapping the enrolment buttons has been updated in MDL-67743 to
use a flexbox grid. It was also updated to add a data- attribute
relating to the participants table id.

The bottom enrol button line should have been updated in the same way.

user/index.php

@@ -442,13 +442,16 @@ if ($bulkoperations) {
 echo '</div>';  // Userlist.
 
 $enrolrenderer = $PAGE->get_renderer('core_enrol');
-echo '<div class="float-right">';
 // Need to re-generate the buttons to avoid having elements with duplicate ids on the page.
 $enrolbuttons = $manager->get_manual_enrol_buttons();
+$enrolbuttonsout = '';
 foreach ($enrolbuttons as $enrolbutton) {
-    echo $enrolrenderer->render($enrolbutton);
+    $enrolbuttonsout .= $enrolrenderer->render($enrolbutton);
 }
-echo '</div>';
+echo html_writer::div($enrolbuttonsout, 'd-flex justify-content-end', [
+    'data-region' => 'wrapper',
+    'data-table-uniqueid' => $participanttable->uniqueid,
+]);
 
 if ($newcourse == 1) {
     $str = get_string('proceedtocourse', 'enrol');