Add an option to manually synchronize Thread credentials

[agners]

Is your feature request related to a problem? Please describe.
If a user has a Google BR in his home, and another Thread network is set as preferred Thread network in Home Assistant Core, there is no way for the user to tell which Thread network is going to be used on commissioning.

The only way I am aware of currently is going through the logs after commissioning, and look for the relevant strings (see https://github.com/home-assistant/android/blob/beta-10164-b285c952/app/src/full/java/io/homeassistant/companion/android/thread/ThreadManagerImpl.kt#L73).

Describe the solution you'd like
Ideally we would inform the user at commissioning time, e.g. before commissioning with a warning: "Your preferred network from Home Assistant could not be set as preferred network on this device. The preferred network on this device is {name of the network}. Do you want to continue commissioning?"

However, depending on how the commissioning flow is triggered we can't show such a message 😢 (or rather, it is already too late). Also, the user might commission a WiFi device, which would make that message irrelevant.

We could warn/inform the user after commissioning, but we (at least currently) don't know what type of device got commissioned. Also, its a bit late at that point 😢

As a stop-gap, so that users have at least a way to tell which network is going to be used, some function in the Companion App Settings would be nice. E.g. a "Synchronize Thread Credentials" button, which then would return a success message normally. And in case the device already has a preferred Thread network, it would tell which one that is.

Describe alternatives you've considered, if any

Additional context