Bass: Handle short broadcast codes

Accept codes from 4 to 16 octets long and add padding zeros
in LSB positions.

Bug: 240929404
Fixes: 240929404
Test: atest BluetoothInstrumentationTests
Change-Id: Icabe59efcaa67ba1dd98f1783efffb2469f02b31
Merged-In: Icabe59efcaa67ba1dd98f1783efffb2469f02b31
(cherry picked from commit 11320c40)