feat(rpc): Add invalidateblock and reconsiderblock RPC methods

[arya2]

Motivation

This PR adds the invalidateblock and reconsiderblock RPC methods to enable more ergonomic integration testing with side chains and chain re-organizations.

This PR is a draft as it's still missing tests.

Closes #8848
Closes #8847
Closes #8846
Closes #8845
Closes #8844
Closes #8843

Depends-On: #9260.

Solution

• Updates non-finalized block write channel message type to an enum with Invalidate and Reconsider variants
• Adds state requests to send those messages to the channel
• Handles the messages in the block write task by calling invalidate_block() or reconsider_block() and updating the chain channels

Related changes:

• Refactors block write task into a struct (feedback on how to improve it further would be appreciated)

Tests

This PR still needs tests.

Follow-up Work

• Add a responder channel to invalidate/reconsider block requests #9265

PR Author's Checklist

• The PR name will make sense to users.
• The PR provides a CHANGELOG summary.
• The solution is tested.
• The documentation is up to date.
• The PR has a priority label.

PR Reviewer's Checklist

• The PR Author's checklist is complete.
• The PR resolves the issue.