RootCanal: Set the default value of acl_data_packet_length to 1023

BlueZ sets HCI_MAX_FRAME_SIZE to 1028 (1024 + 4) for the user socket.
In practice the length check counts the IDC towards the packet length
and the actual limit is 1023 bytes for the ACL payload.

Bug: 326997427
Bug: 356867879
Test: m com.android.btservices
Flag: EXEMPT, tool change
Change-Id: If197a39864a5eda27131aa2f7c58e706ecc4e9dd