AlertService: Switch to FOREGROUND_SERVICE_SYSTEM_EXEMPTED on Android 14+

* New FGS type on Android 14+, needs new permission
* We should migrate to work manager in future which is now recommended to handle background jobs
* Ref: https://developer.android.com/about/versions/14/changes/fgs-types-required#system-exempted



Change-Id: I45aa117861e34aebcc056ccb80b3fc0e2e394161
Signed-off-by: Aayush Gupta <aayushgupta219@gmail.com>