incorrect account representation for oidc in poller when vo is nonetype

[robbarnsley]

Issue with the internal representation where user -> user@None in

rucio/lib/rucio/daemons/conveyor/poller.py

Lines 100 to 101 in b66b5b5

	if oidc_account:
	account = InternalAccount(oidc_account, vo=vo)

This occurs when vo is set to None (when not multi_vo):

rucio/lib/rucio/daemons/conveyor/poller.py

Lines 88 to 89 in b66b5b5

	for (external_host, vo), transfers_for_host in groupby(transfs, key=lambda t: (t['external_host'],
	t['scope'].vo if multi_vo else None)):