Bluetooth: tester: Support BR connect and disconnect features

Create BR connect if the address type is `BTP_BR_ADDRESS_TYPE` when
handling BTP GAP `connect` command.

Disconnect BR connect if the address type is `BTP_BR_ADDRESS_TYPE`
when handling BTP GAP `disconnect` command.

Signed-off-by: Lyle Zhu <lyle.zhu@nxp.com>