Use FLAG_IMMUTABLE for InstallCarrierAppUtils

Require that the PendingIntent be immutable so that a malicious app is
 not able to hijack and mutate any of the details.

Test: Android builds
Bug: 155094269
Change-Id: I8ac155bf53e33474e1fcdb2466743a1e05b92399
Merged-In: I8ac155bf53e33474e1fcdb2466743a1e05b92399
(cherry picked from commit 76decc9e24f07f82af8953c80d2873020a771658)
diff --git a/src/java/com/android/internal/telephony/uicc/InstallCarrierAppUtils.java b/src/java/com/android/internal/telephony/uicc/InstallCarrierAppUtils.java
index 325b3c6..109f72e 100644
--- a/src/java/com/android/internal/telephony/uicc/InstallCarrierAppUtils.java
+++ b/src/java/com/android/internal/telephony/uicc/InstallCarrierAppUtils.java
@@ -68,7 +68,8 @@
                 Settings.Global.INSTALL_CARRIER_APP_NOTIFICATION_PERSISTENT, 1) == 1;
 
         PendingIntent goToStore = PendingIntent.getActivity(context, 0,
-                getPlayStoreIntent(pkgName), PendingIntent.FLAG_UPDATE_CURRENT);
+                getPlayStoreIntent(pkgName), PendingIntent.FLAG_UPDATE_CURRENT
+                        | PendingIntent.FLAG_IMMUTABLE);
 
         Notification.Action goToStoreAction =
                 new Notification.Action.Builder(null, downloadButtonText, goToStore).build();