fix: add Transform implementation for PreCommitInfoExtractorV8

[kasteph]

For earlier parts of the chain, i.e. when miner actors were v8 and below, we get the following error:

{
    "level": "warn",
    "ts": "2023-07-06T00:03:04.875Z",
    "logger": "lily/tasks",
    "caller": "actorstate/task.go:140",
    "msg": "failed to transform with error: ",
    "error": "expected MinerPreCommitInfoV9List type but got: miner.MinerPreCommitInfoList"
}

[Terryhung]

nice!

[birdychang]

Thanks for the fix!

[birdychang]

why is this needed?

[kasteph]

Because of this: https://github.com/filecoin-project/lily/blob/master/storage/sql_test.go#L49 -- it's a convenience function being used in such a test.

Moreover, the mapping of data types between Postgres and Golang is not one-to-one that's why the original code has this condition as well because it tries to equate a Postgres datatype with a fld.SQLType here

[birdychang]

Thank you! This is much better.