[automerge] [DO NOT MERGE] Add unit test for fast pair manager 2p: 4b793e2196

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Nearby/+/17017853

Bug: 202335820
Change-Id: If81e94d9ad2d79f3f4882c6de552a7902c00166d