Show a notification if the Sponsorblock server is down

[xorbital]

Checklist

• I checked, but didn't find any duplicates (open OR closed) of this issue in the repo.
• This feature is related to sponsor or ad blocking and/or has explicitly been rejected upstream.
• I have read the contribution guidelines given at https://github.com/TeamNewPipe/NewPipe/blob/HEAD/.github/CONTRIBUTING.md.
• This issue contains only one feature request. I will open one issue for every feature I want to request.

Describe the feature you want

When trying to contact the Sponsorblock instance results in an error like 502, there should be a notification (a toast notification) and/or an indicator that the instance is down.

Is your feature request related to a problem? Please describe it

In the last few days the main instance has been a bit unstable, as you can see: https://status.sponsor.ajay.app/

Additional context

The main issue with the server has been that the database connection seems to drop every now and then, and while restarting the server manually is quick, waiting for the maintainer to do it can take a few hours.

How will you/everyone benefit from this feature?

Knowing whether the server is down or there are no segments would be nice in that case.

[SameenAhnaf]

Toast message is better than notification in such situation, I think.

[venkat2305]

This would be a killer feature.