Offload status bar network flows to bg

This moves ~100 blocking calls off of main thread during shade open CUJ,
which should significatly improve the performance.

Flag: com.android.systemui.qs_new_tiles
Bug: 384059560
Test: manual. open quick settings, enable or disable Wifi. Verify status
bar correctly reflects the state update.

Change-Id: I60d78be17e95157f02d5ca65fdc57b0607e1bc6a