Skip sanitizing location info for Null Barring CID

If the CellIdentity in BarringInfo is null, then it
doesn't need to be location-info sanitized before
being provided.

Bug: 148695512
Test: atest CarrierApiTest
Change-Id: I8db108a91bcfcdefb48ff3779d972e126bc1d7d2

telephony/java/android/telephony/BarringInfo.java

@@ -321,6 +321,9 @@ public final class BarringInfo implements Parcelable {
     /** @hide */
     @SystemApi
     public @NonNull BarringInfo createLocationInfoSanitizedCopy() {
+        // The only thing that would need sanitizing is the CellIdentity
+        if (mCellIdentity == null) return this;
+
         return new BarringInfo(mCellIdentity.sanitizeLocationInfo(), mBarringServiceInfos);
     }