[DO NOT MERGE] Make screenshot error notification PendingIntent immutable

Bug: 178189250
Test: manual (using POC in bug)
Change-Id: I787915c0493d18500e7531bd0ca7191532441f93
(cherry picked from commit 87adff6976791968f9cd54a340bdae8bcb2c05a4)
diff --git a/packages/SystemUI/src/com/android/systemui/screenshot/ScreenshotNotificationsController.java b/packages/SystemUI/src/com/android/systemui/screenshot/ScreenshotNotificationsController.java
index 42dde40..b8a468e 100644
--- a/packages/SystemUI/src/com/android/systemui/screenshot/ScreenshotNotificationsController.java
+++ b/packages/SystemUI/src/com/android/systemui/screenshot/ScreenshotNotificationsController.java
@@ -252,7 +252,7 @@
                 dpm.createAdminSupportIntent(DevicePolicyManager.POLICY_DISABLE_SCREEN_CAPTURE);
         if (intent != null) {
             final PendingIntent pendingIntent = PendingIntent.getActivityAsUser(
-                    mContext, 0, intent, 0, null, UserHandle.CURRENT);
+                    mContext, 0, intent, PendingIntent.FLAG_IMMUTABLE, null, UserHandle.CURRENT);
             b.setContentIntent(pendingIntent);
         }