fix(trie): correctly populate prefix_sets when building TrieInput from blocks

[GarmashAlex]

Previously, TrieInput built from blocks ignored prefix_sets entirely and extend_with_blocks always appended cached refs. This contradicted the docs and caused incomplete traversal when computing state root from nodes. Now, if a block has no trie updates, we extend prefix_sets from its state (append_ref); otherwise we only append cached nodes/state (append_cached_ref). The same logic is applied to from_blocks_sorted. This aligns behavior with the documented contract and ensures correct walker coverage during state root and proof generation.

[mediocregopher]

Hi @GarmashAlex , you are correct that the docstring from extend_with_blocks is no longer accurate, I've submitted a fix for it here.

In general we do not want to make this change, as an empty trie_updates is not the same as a missing one. If you want to add separate methods which deal with missing trie updates I would be open to that.