mod_roster_command: Fix subscription when the "user JID" is a bare domain. Do not attempt to update the roster when the user is bare domain (e.g. a component), since they don't have rosters and the attempt results in an error: $ prosodyctl mod_roster_command subscribe proxy.example.com contact@example.com xxxxxxxxxxFailed to execute command: Error: /usr/lib/prosody/core/rostermanager.lua:104: attempt to concatenate local 'username' (a nil value) stack traceback: /usr/lib/prosody/core/rostermanager.lua:104: in function 'load_roster' /usr/lib/prosody/core/rostermanager.lua:305: in function 'set_contact_pending_out' mod_roster_command.lua:44: in function 'subscribe'

Introduction
============

This module attempts to sanitize XHTML-IM messages.

It does **not** attempt to sanitize any CSS embedded in `style`
attributes, these are instead stripped by default.

Configuration
=============

  Option                   Type      Default
  ------------------------ --------- ---------
  `strip_xhtml_style`      boolean   `true`
  `bounce_invalid_xhtml`   boolean   `false`