Bluetooth: add missing <algorithm> include

std::copy is provided by <algorithm> header so add it.
This is to fix a build failure on ToT llvm builds where <algorithm>
transitive includes in libc++ have been removed.

The failure was noticed in ChromeOS tot llvm builds where this
repo is imported.

Bug: 228085014
Test: no more std::copy errors.

Change-Id: I3325cf8badb0c5eaffd5afe28f1b047104757cea