Remove the global state for HotShot height

[ImJeremyHe]

Remove the extra global state that we added for the hotshot block height. We don't need this anymore for following reasons:

• Since the L1 arbitrator and block validator have the ability to look back to the previous messages, we don't need to store the hotshot height in the global state for checking the continuity of hotshot block
• Removing the extra global state helps the nitro integration keep in line with the upstream so that we can utilize their tools, such as arbitrum-sdk, without any change.
• This change is also friendly to the migration

This PR:

• Remove the extra global state.
• Remove the continuity check of hotshot block for now, this is not necessary in sovereign sequencer.
• Also remove the staker check which is largely based on this global state. We have to figure out how to do the similar things later.

[Sneh1999]

@ImJeremyHe I would suggest we merge my PR first. This would make the changes in this PR cleaner and the tests will also pass for this PR

[sveitser]

LGTM but one question. I'm also fine with not addressing this right now because we can't panic due to an error in the Message in the replay binary anyway so we will probably have to make significant changes in that region anyway.