Increase non-pruning window

[eskimor]

Because of the messed up v1 descriptor (not properly versioned), we need to fetch the v3_enabled node feature using the relay parent. The issue is that once we allow the relay parent to be older, it might already be pruned and that fetching fails.

Long term fix: Once we enabled the node feature, we can remove the check entirely, which would be the first step to allow "arbitrary old" relay parents. For now, we should just prune a bit later to allow relay parents 20 to 30 blocks old at least to get enough initial slack for resubmissions.

[sandreim]

Why can't we fetch v3 enabled at the scheduling parent we want to use ? Also, it's not realistic that we want to resubmit a 256 blocks old collation.

[skunert]

Yes, default pruning window is 256, nothing to do here.