Add Notification Flag behavior test

Verify the behaviors of FLAG_ONGOING_EVENT, FLAG_NO_CLEAR,
FLAG_FOREGROUND_SERVICE after calling the below API.
1. onClearAll
2. cancelAllNotifications
3. cancelAllNotificationsInt
4. cancelNotificationsFromListener with or without keys

Original author: shunta.sato@sony.com

Bug: 69646960
Test: runtest systemui-notification
Change-Id: I67fef5dbfd61ec9ef6dbee32a0cb80e9c1a2d1b4