regression: block.TimeIotaMs is 0 on exported genesis

[JayT106]

Summary of Bug

think it's a regression issue happens in the current main branch 0a5647e
Was testing the genesis export and tried to verify it but got the error.

the tendermint tendermint/tendermint#9287 has hardcoded TimeIotaMs to 1 ms in main, perhaps we can set it to 1?

relate to #6446

[julienrbrt]

Good catch, seems like we've removed that when upgrading to TM 0.35 but forgot to put it back when we reverted to 0.34.
Would you mind submitting a PR? Otherwise, I can do that.

[JayT106]

Sure, I can submit a PR for that!