Adjust Optimism (Mainnet) TotalDifficulty calculation

[emlautarom1]

Fixes #7626

Changes

• Properly reset the TotalDifficulty at the Bedrock block in Optimism

Types of changes

What types of changes does your code introduce?

• Bugfix (a non-breaking change that fixes an issue)
• New feature (a non-breaking change that adds functionality)
• Breaking change (a change that causes existing functionality not to work as expected)
• Optimization
• Refactoring
• Documentation update
• Build-related changes
• Other: Description

Testing

Requires testing

• Yes
• No

If yes, did you write tests?

• Yes
• No

Notes on testing

Tested by running a node using the op-mainnet configuration. All Old Headers were downloaded without any issues and proper TotalDifficulty is always calculated correctly.

Documentation

Requires documentation update

• Yes
• No

This change should be internal so no need to update docs.

Requires explanation in Release Notes

• Yes
• No

Remarks

Some changes required adjusting the DI modules specific for Optimism. It was not as straightforward as I would have expected it to be.

[asdacap]

This check is not needed. Just have one OptimismSynchronizerModule for just optimism configuration, the register it later after MergeSynchronizerModule.

[emlautarom1]

The check is actually needed since we want to use a particular difficulty calculation strategy in Optimism Mainnet and not in, for example, Optimism Sepolia.

[asdacap]

That is unfortunate.