DO NOT MERGE Drop Bluetooth connection with weak encryption key

This patch requires Bluetooth chip to support HCI Read Encryption Key Size
command and will cause Bluetooth to crash if this command is not supported
on a device. Such device should not take this patch and should look for
alternative solution to drop Bluetooth connection with weak encryption key.

Bug: 124301137
Change-Id: Id4b6b4e765628397a79e6806f45c2cd27acebd5b
(cherry picked from commit 2ea24ede)