refactor(l2): restart processes with the proposed API

[fborello-lambda]

Motivation

The error handling should be the same for all processes, unwraps have to be handled with the ? operator so that the api can restart the process if any Err is raised.

Description

• Use the same API proposed by the PR feat(l2): refactor processes to handle errors at the top and use a common api #1230, removing the unwraps.
  • L2: handle unwraps in prover_server.rs #1168
• When we have an error we "restart" the process, this handles the not committed block error.
  • L2: wait or handle not committed block #1165
• The order of the require statements in the verify() function of the OnChainProposer contract was changed to throw the correct error. The error handling with the proposed API does the rest.
  • L2: Differentiate require Errors in OnChainProposer Verification #1164.

Closes #1168
Closes #1165
Closes #1164