Plumb WiFi multicast filter through to ApfFilter

Use APF to implement WifiManager.MulticastLock, if APF isn't available
fallback to the present behavior of using DRIVER RXFILTER. Since we
don't know whether APF is supported until we're connected, postpone
enabling/disabling the multicast filter until then; this should be
fine as there isn't much need to filter packets if there aren't any
packets going by since we're not connected.

Bug: 26238573
Change-Id: I862c053f1c8c3a41de50c2951cf14b3ca6923a2a