Use new PackageMonitor#register() without externalStorage parameter

The externalStorage is not be used now, we are migrate to use new
method.

Bug: 29385425
Test: build
Change-Id: I361cc183bf2cd392f24221599abdbc9dbdfd8e3b

services/core/java/com/android/server/StorageManagerService.java

@@ -2069,7 +2069,7 @@ class StorageManagerService extends IStorageManager.Stub
                 }
             };
             // TODO(b/149391976): Use different handler?
-            monitor.register(mContext, user, true, mHandler);
+            monitor.register(mContext, user, mHandler);
             mPackageMonitorsForUser.put(userId, monitor);
         } else {
             Slog.w(TAG, "PackageMonitor is already registered for: " + userId);