While implementing the changes for FrostFS ID it became obvious, that
committee signature check can be rather costly (`getCommittee` call +
multiaddress construction + checking witness). In real scenarious it
will mostly fail, so it makes sense do it last.
Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>
We don't want to return Null from contract when list is empty
because generated policy client cannot parse this.
Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>
