[MS62.1] Start NetworkStatsService from the module

NetworkStatsService is going to be moved into Connectivity mainlne
module and it will be not visible to SystemServiceResistry after
migration done. Thus:
1. Register service in NetworkStatsServiceInitialalizer, a separate
   initializer is needed because the service needs to be created
   before NetworkPolicyManagerService's initialization.
2. Call SystemReady at PHASE_ACTIVITY_MANAGER_READY phase where
   it needs to be ready before StatsPullAtomService pulls at
   PHASE_THIRD_PARTY_APPS_CAN_START.
3. Register manager in ConnectivityFrameworkInitializerTiramisu
   instead of SystemServiceRegistery.

Test: atest FrameworksNetTests CtsNetTestCases NetworkUsageStatsTest
Bug: 204830222
  (cherry-picked from ag/16688794)
Change-Id: I95020d816ed613ce3480a0720a5b71dcdc7fab72
Merged-In: I95020d816ed613ce3480a0720a5b71dcdc7fab72

framework-t/src/android/net/ConnectivityFrameworkInitializerTiramisu.java

@@ -18,6 +18,7 @@ package android.net;
 
 import android.annotation.SystemApi;
 import android.app.SystemServiceRegistry;
+import android.app.usage.NetworkStatsManager;
 import android.content.Context;
 import android.net.nsd.INsdManager;
 import android.net.nsd.NsdManager;
@@ -57,5 +58,15 @@ public final class ConnectivityFrameworkInitializerTiramisu {
                     return new IpSecManager(context, service);
                 }
         );
+
+        SystemServiceRegistry.registerContextAwareService(
+                Context.NETWORK_STATS_SERVICE,
+                NetworkStatsManager.class,
+                (context, serviceBinder) -> {
+                    INetworkStatsService service =
+                            INetworkStatsService.Stub.asInterface(serviceBinder);
+                    return new NetworkStatsManager(context, service);
+                }
+        );
     }
 }