Merge "Do not allow null signal thresholds in SignalStrengthUpdateRequest" am: b6aa5b7d37 am: 59cd9748a2

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1894915

Change-Id: I7fc547bcec6a9d16b2a3e148a4fbfaae50f66285