bluetooth: Move First Device Chooser to tests

Now that we have a chooser on all supported platforms we can move the
First Device Chooser fallback to content shell, the only place where it's needed.

BUG=524780

Review-Url: https://codereview.chromium.org/2110813002
Cr-Commit-Position: refs/heads/master@{#403358}
10 files changed