phabricator: pass ui instead of repo to callconduit This will help us make `hg debugcallconduit` work outside a hg repo as next patch will mark that command as no repo. Differential Revision: https://phab.mercurial-scm.org/D6498

{
    "conduit_uri": "https://phab.mercurial-scm.org/api",
    "repository.callsign": "HG",
    "arc.land.onto.default": "@",
    "base": "hg:.^"
}