Update to 0.1.50 am: f833bced20 am: 6a58d211c4 am: 676ed34add

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/async-trait/+/1682043

Change-Id: I8e743118e3b238baf3bb38bd22a547eaa53ff261