Fixes for unpick (and adapt to V4)

[0x189D7997]

Unpick V4 requires newly introduced class member checker to be set when building a DataDrivenGrouper.

Said member checker can be obtained in a the same way as an inheritance checker and this is what did I here. I am not too familiar with unpick so this might be not the right way to do it but it seems to work and pass all the tests.
Needs to be sanity checked by someone with better understanding of matter.

[0x189D7997]

There is one mode issue I'd like to fix here.
When one or more of the requested versions do not have the chosen or fallback unpick (and fallback does not include none) the applications hangs indefinitely.

I'd like to do this by excluding versions that do not meet unpick requirements, however there are two more approaches I can think of:

• Have none as the default fallback
• Crash before doing anything if this happens.

I'm going with excluding versions like mappings do but I can implement a different approach if needed,

[0x189D7997]

@WinPlay02 can you please re-run CI for this one?
The new fail is inconsistent and is not caused by the changes.
Possibly because we are sending too many requests to Skyrising host and hit some sort of rate limit. #40 might help with this.

Also, there is no point of running CI on any other PRs until this one is merged.

[WinPlay02]

Thanks for taking care of this