Import protobuf-json-mapping crate. am: bb8920e11b am: daeeea76da am: 52c5d139a8 am: e42e8d5c1c

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/protobuf-json-mapping/+/2514115

Change-Id: I7219d31f79e95f90e95f6c777f4de382f0f9fee3
Signed-off-by: Automerger Merge Worker <[email protected]>