Nfc: Replace use of android.view.Window->isDestroyed()

The code was testing to know if an Activity is destroyed,
directly use Activity->isDestroyed() to this purpose.

Bug: 244264995
Test: m
Change-Id: Ia3845819f65214367648f35c8e1ad685f2e00c85

core/java/android/nfc/NfcActivityManager.java

@@ -122,7 +122,7 @@ public final class NfcActivityManager extends IAppCallback.Stub
         Binder token;
 
         public NfcActivityState(Activity activity) {
-            if (activity.getWindow().isDestroyed()) {
+            if (activity.isDestroyed()) {
                 throw new IllegalStateException("activity is already destroyed");
             }
             // Check if activity is resumed right now, as we will not