user_group_pill: Accept setting_type as parameter in typeahead_source.

We currently use the pills UI only for can_manage_group setting so
it is fine to pass setting type as "group" directly to
get_realm_user_groups_for_setting, but it would be better to just
accept setting_type as parameter in typeahead_source and pass that
to get_realm_user_groups_for_setting as other settings will also
use the pills UI in future.

web/src/user_group_edit.js

@@ -172,6 +172,7 @@ function show_general_settings(group) {
     settings_components.create_group_setting_widget({
         $pill_container,
         setting_name: "can_manage_group",
+        setting_type: "group",
         group,
     });
     update_general_panel_ui(group);