Set gesture exclusion zone on glanceable hub

Right now the bouncer swipe gesture area overlaps the bottom row of
widgets a tiny bit. Setting an exclusion zone prevents this from
happening.

Fix: 335505186
Fix: 337080140
Bug: 335505186
Test: atest GlanceableHubContainerControllerTest
Flag: communal.communal_hub
Change-Id: Iad4c2658a98771f5aad2e7098b0cfd102792bfaa