Fix notification shelf icon showing on top of snooze leave behind

Also fixes an issue where the guts closed listener would always call
onHeightChanged because the notification isn’t marked as removed
until after the listener gets called.

Fixes: 34866027
Test: Manual - have one notification, snooze it
Change-Id: Ic67bdb353b8bb5df8bdaaf6d3e71ade7da05ee46