[security] SubscriptionGroup is exposed to unprivileged callers

SubscriptionInfo.mGroupUUID is not cleared in
conditionallyRemoveIdentifiers if the caller only has READ_PHONE_STATE
(based on a check to checkReadPhoneState) and not READ_DEVICE_IDENTIFIERS.
Bug: 181053462
Test: atest SubscriptionManagerTest

Change-Id: Ic2b62523330dc6e2169ad851715c4ab3da3b29cf
Merged-In: Ic2b62523330dc6e2169ad851715c4ab3da3b29cf

telephony/java/android/telephony/SubscriptionInfo.java

@@ -519,6 +519,13 @@ public class SubscriptionInfo implements Parcelable {
         return mGroupUUID;
     }
 
+    /**
+     * @hide
+     */
+    public void clearGroupUuid() {
+        this.mGroupUUID = null;
+    }
+
     /**
      * @hide
      */