Update BlockhashQuery to more correctly determine blockhash validity

[2501babe]

Problem

BlockhashQuery uses is_blockhash_valid. as discussed here: #23949 (comment), this can return a false negative if querying a node thats behind the chain. the better way is to compare the blockhash last valid block height to the result of get_block_height

Proposed Solution

ideally we could keep the interface the same and determine the last valid height from the hash, but i dont know if this is actually possible?

alternatively we can retain the last valid height and pass it through or store it in BlockhashQuery, but this means either breaking the interface of new or adding another constructor and falling back to is_blockhash_valid in absence of a height. obviously the first solution is preferred if possible

[2501babe]

we ended up not needing BlockhashQuery after all