Validation should fail before we hit the end of a snapshot

We should tell the user if they're trying to validate too many tipsets (e.g more than their snapshot will allow)

> Validation is expected to fail when you reach the tail of the snapshot `--height=-1100` is as far as you can go

_Originally posted by @aatifsyed in https://github.com/ChainSafe/forest/issues/3179#issuecomment-1633038834_

Start by tracing the validation path for tipsets against the snapshot boundary. Reproduce validation with a height beyond the snapshot, such as `--height=-1100`, and confirm it fails before reaching the snapshot tail with a clear error.

Written by the indexing model from the issue text.