Delay showing hub onboarding bottom sheet.

There should be a 1-second delay (after entering hub) before the bottom
sheet appears.

Bug: 392924444
Test: Manually by observing that the bottom sheet appears after a delay.
Flag: com.android.systemui.glanceable_hub_v2

Change-Id: I47b648ee4552656d3660489bfd821dedb952f8af