Adding flag com.android.server.notification.notification_force_group_singletons to RELEASE_CONFIG_TRUNKFOOD_STAGING. This commit was automatically created by advancing a workflow in Gantry. Manual edits to this file are forbidden. If you need to rollback, please visit https://releasetracker.partner.android.com/changes/a77330i000001?build_unique_id=Frontend:+android_platform_systemui,+Study:+ComAndroidServerNotificationNotificationForceGroupSingletonsLaunch to begin a rollback. POSTSUBMIT ERRORS: If this change breaks postsubmits, please revert it and attach the associated bugs to the reverted CL's description. Flag: com.android.server.notification.notification_force_group_singletons Ignore-AOSP-First: AConfig change for future AOSP release Bug: 336488844 Change-Id: I07f98c5cecb735ac0f3f38f6efa9bc916cd7783b