Fix Settings crashing while displaying phone number slice.

Check if the SubscriptionInfo list is empty to avoid the IndexOutOfBoundsException.

Fixes: 133258244
Test: maunal & robotest

Change-Id: I837f6761ba2b53823f0126f734f65875a30e34dd

src/com/android/settings/deviceinfo/PhoneNumberPreferenceController.java

@@ -120,7 +120,7 @@ public class PhoneNumberPreferenceController extends BasePreferenceController {
     private CharSequence getFirstPhoneNumber() {
         final List<SubscriptionInfo> subscriptionInfoList =
                 mSubscriptionManager.getActiveSubscriptionInfoList(true);
-        if (subscriptionInfoList == null) {
+        if (subscriptionInfoList == null || subscriptionInfoList.isEmpty()) {
             return mContext.getText(R.string.device_info_default);
         }