ESPProvisionManager crash: stopESPDevicesSearch() unexpected found nil

[MartinaeyNL]

Description

One of the issues specific to the iOS version of the ESPProvisionProvider is that it crashes during stopESPDevicesSearch().
It occurs when the provider is initialized, and the first command is STOP_BLE_SCAN before START_BLE_SCAN is sent.
The app crashes in full immediately, without any error message etc.

This is because the Web UI sends STOP_BLE_SCAN when exiting the onboarding flow, whatever step they are in.
It is working OK on Android, but fails with a null exception on iOS.

Expected behavior

The lib doesn't crash the app, doesn't show anything to the user (silent approach), and simply sends an errorCode back using the ConsoleProvider.

[ebariaux]

ESPProvisionProvider is Espressif code and the crash is due to a force unwrapping of a nil value.