Don't inform usage stats of interaction for a toast

If the process is forced to the foreground due to a toast,
don't inform usage stats of an interaction. Otherwise app standby
will be defeated easily.

Bug: 31544592
Test: cts-tradefed run commandAndExit cts -m CtsHostsideNetworkTests -t com.android.cts.net.HostsideRestrictBackgroundNetworkTests#testAppIdle_toast
Change-Id: I100d839ef8cf361704fd5db4b26dcc878672a235