Add padding between hotseat and insets in multiwindow landscape

Right now there's almost no room between the hotseat icons and the
nav  bar in this mode, and it looks kind of bad. It also causes
b/109946631 which is fixed by this change.

Also fix placement of popup in RTL landscape (was incorrectly inset)

Bug: 109946631
Change-Id: I324485da0048b907776b16b719b631c5314e5696