BR/EDR service access should not block on LE encrypting state

BR/EDR and LE transport share the encryption state. As a result if LE
encryption is pending, BR/EDR service access gets blocked. On LE
encryption change, the pending BR/EDR service access requests are not
unblocked.
This change introduces a separate encrypting state for LE transports.

Change-Id: I16c079a6c1af3d3659230f19ee013b605c5bc9e6
Test: Pair and connect with buds with Spatial audio and CTKD
Bug: 281198014