uwb: Rewrite implementation of sendUciMessage to use the opened File am: 77971b371b

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2712294

Change-Id: Ie7f4be53bd35e4af750e21ec4614588a04754d21
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>