Fix null PendingIntent in network listens

In S ConnectivityService was changed to use getActiveRequest() to fill
EXTRA_NETWORK_REQUEST, but there is no active request in the case of
listens.

When getActiveRequest() is missing, use the first mRequest instead. This
should match previous behavior.

Bug: 191713869
Test: atest android.net.cts.ConnectivityManagerTest
Original-Change: https://android-review.googlesource.com/1748153
Merged-In: Id7343a4cc020aba16b7979b16334721c56b2839c
Change-Id: Id7343a4cc020aba16b7979b16334721c56b2839c
2 files changed