[Catalog] Ensure that the navigation bar is always visible when nodes appear.
[Catalog] Ensure that the navigation bar is always visible when nodes appear.

Reviewers: #material_components_ios_owners, randallli

Reviewed By: #material_components_ios_owners, randallli

Projects: #material_components_ios

Differential Revision: http://codereview.cc/D121

willlarche/material-components-ios,willlarche/material-components-ios,chriscox/material-components-ios,sigito/material-components-ios,samnm/material-components-ios,chriscox/material-components-ios,Eccelor/material-components-ios,brianjmoore/material-components-ios,Eccelor/material-components-ios,sigito/material-components-ios,material-components/material-components-ios,brianjmoore/material-components-ios,randallli/material-components-ios,chriscox/material-components-ios,randallli/material-components-ios,samnm/material-components-ios,randallli/material-components-ios,sigito/material-components-ios,Eccelor/material-components-ios,samnm/material-components-ios,randallli/material-components-ios,sigito/material-components-ios,brianjmoore/material-components-ios,material-components/material-components-ios,chriscox/material-components-ios,willlarche/material-components-ios,samnm/material-components-ios,randallli/material-components-ios,material-components/material-components-ios,Eccelor/material-components-ios,willlarche/material-components-ios,Eccelor/material-components-ios,randallli/material-components-ios,brianjmoore/material-components-ios,willlarche/material-components-ios,chriscox/material-components-ios,material-components/material-components-ios,material-components/material-components-ios,brianjmoore/material-components-ios,sigito/material-components-ios,samnm/material-components-ios