config: relax replication.peers autobuild constraints

Before this commit all the peers of the given replicaset were obligated
to have suitable URI to connect -- either iproto.advertise.peer or one
of iproto.listen URIs.

Now replication.peers is successfully constructed if at least one
suitable URI is constructed (except URI of the given instance itself).

However, if an unknown user is used in the iproto.advertise.peer option
of any peer, it is considered as an error (startup failure), just like
before.

The testing code for unsuccessful cases of replication.peers
autobuilding is rewritten to reflect that just one bad peer doesn't
cause a startup failure anymore. Now it also needs stripping of log
messages, because the peers autobuilding tells about unsuitable URIs.

Part of #8810

NO_DOC=the old behavior was not released, the documentation request will
       be registered manually
NO_CHANGELOG=see NO_DOC