Floss: Fix bug of missing monitor_handle

Adding missing change from https://r.android.com/q/3dca872562. When
converting AdvertisingTrackInfo to Rust, we need to copy the new field
monitor_handle.

Bug: 268682529
Tag: #floss
Test: Manual - Test Floss on Chrome OS with Fast Pair

Change-Id: I28c1f293537d50c71e041e63b2b33bb5b2479c43