Backport !5848 - Proto: Increase nonce revelation threshold from 32 to 256 blocks

Context

!5848 (merged) is required in protocol Kathmandu. Cherry-picked commit from it using the following commands.

$ git checkout -b proto-k-backport-5848
$ git cherry-pick 39651604e7160febdf04c648ad055ea741e4f643

Manually testing the MR

Check CI.