Add New Radio or Model Config Option to disable Trainer Still Connected warning at shutdown

[TodWulff]

Is there an existing issue for this feature request?

• [X] I have searched the existing issues

Is your feature request related to a problem?

With a perpetually connected Nano BLE Sense Rev 2 connected to the Aux_ UART ports (as a Headtracker BLE Receiver), on the Radio Master TX16S MKII and MT12 radios (being configured as Radio Aux_ SBus Trainer | Model Master Trainer), when powering down the radio, there is a nuisance warning of Trainer Still Connected.

Describe the solution you'd like

It is desired to have a config option to suppress this warning at power down, as the Arduino SBC BLE radio is perpetually connected internally - a warning of a perpetual condition is not warranted.

Describe alternatives you've considered

I've considered both approaches of having this option in the radio hardware or the model configuration. Warning suppression is the feature desired, whether the option is broad (done in Radio configuration) or model-specific (done in Model configuration) is moot, as long as the goal of removing the nagging warning can be attained. Thank you, in advance.

Additional context

I experience this issue on my TX16S MKII color LCD radios and B&W MT12 radio.