[automerger skipped] Fix NullPointerException on addErrorCode when input is...

[automerger skipped] Fix NullPointerException on addErrorCode when input is Invalid error code am: ad90e1bf -s ours am: 4ab15ede -s ours am: 4f6eb0ab -s ours am: 54be984d -s ours

am skip reason: Change-Id I43b8415ab98b4cf6520c3240dc544a9f62730a4e with SHA-1 ad90e1bf is in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/NetworkStack/+/11987398

Change-Id: I5212cab27c4b2b60fb1fa3224c4de2715aa8445f