mod_delegation: use clean_xmlns to remove jabber:client namespace from node: for the same reason as in mod_privilege, `jabber:client` namespace is removed with the clean_xmlns method coming from there. Furthermore, the forwarded <iq> stanza use the `jabber:client` xmlns while the stanza may come from a component with e.g. `jabber:component:accept` xmlns, this can lead to inconsistencies between the <iq> stanza and children (like <error> element).

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summary: Remote Roster Management
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Introduction
============

This module adds support for [XEP-0321: Remote Roster Management] which
is commonly used to allow components such as transports to modify the
rosters of local users.