Hide room list show less button if it would do nothing
Hide room list show less button if it would do nothing

Signed-off-by: ☕ Tim <tim@wants.coffee>

On the new rooms list, if the show less button wouldn't result in a
smaller list, don't show it.

Fixes vector-im/riot-web#14219

matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk