API feedback: WifiNetworkStateChanged missing IntDefs

Adding missing IntDefs as well as fixes a bug where the listener wasn't
getting invoked on disconnect when wifi scanning is turned on.

Bug: 268196154
Bug: 269204554
Test: atest WifiManagerTest#testWifiNetworkStateChangeListener
Test: atest com.android.server.wifi
Change-Id: I8ebbabe24eb1c670cb5167bb8ac90e4dbcef47d5
3 files changed