Sequencer checks

[just-mitch]

The sequencer will have the ability to inspect functions that are enqueued for setup/teardown to decide if it wants to take the risk to execute the transaction: if these functions do in fact revert, the transaction is invalid and cannot be added to the chain, thus the sequencers will not be paid for the work they did.

Tasks

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1. Update sequencer to validate fee payer gas balance #4091
   +0
   
2. Sequencer can whitelist contracts for setup and teardown #5000
   +0
   
3. Clean up tx object of unneeded fields #3417
   A-protocol +1
4. Sequencer should check function selector being used to pay the fee #5401
   +0
5. Sequencer checks that fee_payer has sufficient FPA #5916
   +0