Enable bubbles home gesture by default

Update feature flag for bubbles home gesture handling to be on by
default.

Bug: 170163464
Test: manually verified that home gesture feature is enabled on a a fresh build
Test: atest PlatformScenarioTests:android.platform.test.scenario.sysui.bubble
Change-Id: Ie6bdea919dfaf6448b3c57756cd06993a6a60ce7