MDL-76975 admin: Move AMD dependencies to data attribute to fix overflow

Since there is a 1024 length limit on arguments passed through
js_call_amd(), we pass it through a HTML element dataset to avoid
this limit.

admin/settings.php

@@ -165,10 +165,8 @@ if (empty($SITE->fullname)) {
 $PAGE->requires->js_call_amd('core_form/changechecker', 'watchFormById', ['adminsettings']);
 
 if ($settingspage->has_dependencies()) {
-    $opts = [
-        'dependencies' => $settingspage->get_dependencies_for_javascript()
-    ];
-    $PAGE->requires->js_call_amd('core/showhidesettings', 'init', [$opts]);
+    $context = ['dependencies' => json_encode($settingspage->get_dependencies_for_javascript())];
+    echo $OUTPUT->render_from_template('core_admin/settings_showhide', $context);
 }
 
 echo $OUTPUT->footer();