The Pybricks firmware now includes the BLE Device Information Service
to provide firmware and Pybricks protocol versions.
For now, checking that the service is present is enough to know that the
firmware is up to date. But we will need to add additional checks as
soon as the protocol is changed.
This fixes the first notification being missed due to the notification
handler not being started until after notifications are enabled.
It also fixes the DidConnect action changing the state to Unknown after
a notification was received that set the state to a known value.
This is the beginning of the BLE Pybricks service implementation, so
changes are made to get a handle to the Pybricks control characteristic
and enable notifications.
Currently, only one event (the status report event) and no commands are
implemented on this characteristic.
The new status report event replaces monitoring the UART for >>>>
strings to get the current hub state.
Also includes some minor cleanup in the ble-uart/actions for consistency.
David Lechner