Added null check for Intents without action string am: 8d25bcd35c am: ac3c4528d4

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/services/AlternativeNetworkAccess/+/18159367

Change-Id: I03b4e406ae1bd56298ef25789e277cc267a49999
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>