Allow Bluetooth to use privapp_allowlist

Apparently there's some special case-code in package manager that
scans apps as privileged regardless of their location. BT is one
such app -- so allow it to specify a privapp allowlist even though
it isn't in priv-app.

Bug: 284500052
Test: use privapp_allowlist in Bluetooth and its overriddes
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:a91268a690e2aa98a0fa7b376a948a48f41b1265)
Merged-In: Ib9ac86ebc45087a176100fe8df07db7bf81a85a7
Change-Id: Ib9ac86ebc45087a176100fe8df07db7bf81a85a7