nit: Use sdk blocks instead of tendermint blocks.

[DimitrisJim]

Description

Reference: cosmos/cosmos-sdk#3544

basically saw it since its the only thing my editor is currently complaining about

Commit Message / Changelog Entry

nit: Use sdk blocks instead of tendermint blocks.

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[chatton]

I just noticed the comment about why we chose to use res.Block instead of res.SdkBlock. I think we will need to double check the versions we support and when we can actually make this change.

[chatton]

I won't leave an approval as I now have some commits here, but I think this new interface type should do the trick!

[colin-axner]

LGTM

requested changes applied