Update how the microcontroller checks the Bluetooth connection status

As far as I am aware of, there are no in-built functions that can be used to check if the Bluetooth module has established a successful connection with the app. As a result, the microcontroller has no idea if the app is connected or not.

However, the app knows if a successful connection has been established. So, a work around has been developed which solves this issue.

When a successful connection has been made, the app sends the device a message informing it a connection has been established. This was, the microcontroller knows that is connected to the app.

This needs to be fixed by investigating if there are any in-built commands which check for connection status. A good starting point is AT-commands.

Start by reviewing the microcontroller code and the Bluetooth connection flow described in the issue, then investigate the module's AT-commands for a built-in connection-status check. Compare the result with the existing app message workaround; the work is done when the microcontroller can determine whether the app connection was established without relying on that workaround.

Written by the indexing model from the issue text.