Send the probe status from NetworkMonitor to ConnectivityService

Provide a new callback for NetworkMonitor to notify
ConnectivityService that which probes are completed.

Bug: 113242081
Test: atest NetworkStackTests
Change-Id: I81f22002bc9a59c7c49d471e15e67722613d61a3

• common/networkstackclient/Android.bp[diff]
• common/networkstackclient/src/android/net/INetworkMonitorCallbacks.aidl[diff]
• src/com/android/server/connectivity/NetworkMonitor.java[diff]
• tests/unit/src/com/android/server/connectivity/NetworkMonitorTest.java[diff]