* ref(display-name): do not pass in display name

The component gets the state itself from redux.

* fix(display-name): do not default name to placeholder name

The web display name component supports inline editing of
the name. Problems can occur when the displayed name
differs from the actual saved name, because participants
without a display name, including the local user, have
a different, default display name displayed. So when
editing starts, the input field is populated with the
default name. To workaround such while supporting fetching
the display name using mapStateToProps, pass in both the
name which should be shown and the name value saved in
settings.

* ref(display-name): rename methods