Skip filtering apps that have indicator already running.

Only non-system & non-background apps should trigger the location indicator. But if the location indicator is already visible, keep it in the list during the holding period.

Fixes: 435271798
Change-Id: If990226baeb91c1cbb73fb70d8e00e6584776d01
Test: on device
Flag: android.location.flags.location_indicators_enabled