Do not push disconnect error code when socket is connected state

App error codes are mainly to send exceptions to applications when socket connection fails. Stack don't need to push these error codes when socket is already connected and l2cap connection is removed from remote.

Test: mmm packages/modules/Bluetooth
Test: Tested manually to ensure no unexpected data on socket read after disconnect
Flag: com.android.bluetooth.flags.donot_push_error_code_to_app_when_connected
Bug: 359992434
Bug: 365844219

Change-Id: I5a026fd01a998df74eea8b1700ed79bad45a9f29