Add final attempt to reconnect in radio bridge

[microbit-grace]

In response to microbit-foundation/ml-trainer#281 (comment)

[microbit-robert]

This looks good and relicates the current behaviour in the ml prototype.

I've raised a few minor things, either for change or discussion, but would be happy to merge as is and come back to if necessary.

I don't know if it's possible or not, but it would be nice if, when we lost connection, we could probe the bridge device to see if it had been reset and then restart the communication between the micro:bits without having to wait for the connectTimeoutDuration which is currently 10 seconds. One to come back to.

[microbit-grace]

I don't know if it's possible or not, but it would be nice if, when we lost connection, we could probe the bridge device to see if it had been reset and then restart the communication between the micro:bits without having to wait for the connectTimeoutDuration which is currently 10 seconds. One to come back to.

Interesting idea. That would be nice UX-wise, though yes, perhaps something to come back to.

[microbit-robert]

LGTM, thanks.