Always read LE appearance if CoD is unknown

Class of device is discovered over BR/EDR transport either through inquiry response or remote initiated connection request. If pairing is started over BR/EDR without discovering over BR/EDR transport, the class of device may not be discovered. In such cases, appearance value can be found over LE transport if the remote device is a dual mode device.
This change now allows appearance value to be read for bonded devices as well if Class of device is unknown.

Change-Id: I8336d45b875abf24b0b3d7a27e3805de3e8e0f4b
Test: mmm packages/modules/Bluetooth
Flag: com.android.bluetooth.flags.le_appearance_after_ctkd
Bug: 356614762
Bug: 386835787