Update flicker app targetSDK

Update the following:
1. PendingIntent requires FLAG_MUTABLE
2. Bubble/Notification requires POST_NOTIFICATIONS
3. registerReceiver requires RECEIVER_EXPORTED
4. Opt-out force edge-to-edge

Bug: 306666082
Test: pass presubmit
Test: atest PlatformScenarioTests:BackAndHomeOnGMail
Change-Id: I90de055be9c9c270b6815b719209ca8407431d39