fix(cast): pass blocknum to cast storage rather than always using latest

[g-01234]

Motivation

cast storage currently passes None to provider.get_storage_at() for block, rather than the block number if provided by the user. This causes storage for the latest block to always be pulled, regardless of what the user provides.

Solution

Pass the block (already a flag for storage and parsed as BlockId ) along to provider.get_storage_at().

[g-01234]

Merge went thru as I was typing this, but @igorline pointed out that the test case I included doesn't actually cover the branch I modified (--block works as expected when querying for a single slot). Happy to remove it if desired, however the other two branches require either: 1) a foundry project, or 2) an etherscan API key (branch1, branch2). Not sure how you guys would handle such a case in cast test. Can confirm it's working as expected locally though (note tokenCounter increasing between blocks)