Ensure we don't record 0 MCC/MNC.

We see lots of traces where correct-looking MCC/MNC are replaced by 0/0.

Bug: 285879449
Test: recorded a trace.
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:c9bb739def1dbf743e892e1950aeaaf7b4c8f33d)
Merged-In: I532e2b97f7fb9337850613d56f70cfd3377462f0
Change-Id: I532e2b97f7fb9337850613d56f70cfd3377462f0
1 file changed