Update UpstreamNetworkMonitor to use custom Handlers

Test: as follows
    - built (bullhead)
    - flashed
    - booted
    - runtest frameworks-net passes
Bug: 32130437
Bug: 32163131

Change-Id: I2bc3f87cdf7fa6392b4750eb8adb4ea33c6a3f43
diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 7c3e153..30afdc2 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -2923,15 +2923,6 @@
      * @hide
      */
     public void requestNetwork(NetworkRequest request, NetworkCallback networkCallback,
-            int timeoutMs, int legacyType) {
-        requestNetwork(request, networkCallback, timeoutMs, legacyType, getDefaultHandler());
-    }
-
-    /**
-     * Helper function to request a network with a particular legacy type.
-     * @hide
-     */
-    private void requestNetwork(NetworkRequest request, NetworkCallback networkCallback,
             int timeoutMs, int legacyType, Handler handler) {
         CallbackHandler cbHandler = new CallbackHandler(handler);
         NetworkCapabilities nc = request.networkCapabilities;
@@ -3033,7 +3024,7 @@
     public void requestNetwork(NetworkRequest request, NetworkCallback networkCallback,
             int timeoutMs) {
         int legacyType = inferLegacyTypeForNetworkCapabilities(request.networkCapabilities);
-        requestNetwork(request, networkCallback, timeoutMs, legacyType);
+        requestNetwork(request, networkCallback, timeoutMs, legacyType, getDefaultHandler());
     }