Repost PageAgnostic mode notification when dismissed

Device is in experimental mode when using 16kB developer option.
When the notification is dimissed, repost it again.

Bug: 351029724
Test: m Settings && adb install -r $ANDROID_PRODUCT_OUT/system_ext/priv-app/Settings/Settings.apk
Flag: EXEMPT bugfix
Change-Id: Ie579b6c4dd060b165c6cc8ae635d48e257d49bec