uwb: Rewrite implementation of sendUciMessage to use the opened File am: 77971b371b am: db8a7b7c5d

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

Change-Id: Iac74bc24c7a8167228a17c15858e661acaa48cd1
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>