Fix how imported-but-not-found changesets are displayed
Created by: mrnugget
This changes the ExternalChangesetInfoCell to not show the ()
when the
changeset couldn't be found.
It also updates the story to include an imported-but-not-found changeset
and makes them more accurate by setting diff: null
.
@eseliger I tried my best. Would appreciate a Zoom call if you have suggestions for improvements.