ezDV does not unregister itself from SmartSDR

[tmiw]

Currently there is logic in ezDV (in FlexTcpTask.cpp) that unregisters itself from Flex radios when shutting down, and could presumably be run as well after a brief disconnection. However, when running this logic, the radio itself crashes. Thus, in the current FW, this logic is disabled.

The crash is being tracked by FlexRadio as SMART-9473 and this issue will be open until confirmed to be fixed (and the logic can be reenabled).