Fix violation in DecorContext

The issue happens when activity is launched on the secondary
display. It's because the base context of DecorContext is
a DisplayContext, but we should check #isConfigurationContext in
associatd window's Context instead, like DecorContext#isUiContext

fixes: 242571036
Test: manual - launch activity on the secondary display

Change-Id: Ie2659fb31248ad64099018bfebb6a6b43c72f466

core/java/com/android/internal/policy/DecorContext.java

@@ -137,4 +137,13 @@ public class DecorContext extends ContextThemeWrapper {
         }
         return false;
     }
+
+    @Override
+    public boolean isConfigurationContext() {
+        Context context = mContext.get();
+        if (context != null) {
+            return context.isConfigurationContext();
+        }
+        return false;
+    }
 }