Emit event when a block is finalized from the bft module - Closes #3908

[pablitovicente]

What was the problem?

An event was not being emitted when finalized height changed in finality manager

How did I solve it?

• by extending event emitter in finality manager
• by emitting an event on change of finalized height
• by listening to the event in the BFT class

How to manually test it?

Review checklist

• The PR resolves Emit event when a block is finalized from the bft module #3908
• All new code is covered with unit tests
• Relevant integration / functional tests are added
• Commit messages follow the commit guidelines
• Documentation has been added/updated

[lsilvs]

Would be possible to use channel.publish and channel.subscribe instead?

[pablitovicente]

Would be possible to use channel.publish and channel.subscribe instead?

There was a talk about this and it seems for now we'll use emit() I do agree that maybe before completing bft we can agree on changing to channel.subscribe/publish on all the code? @nazarhussain @shuse2 ?

[shuse2]

Since BFT will be separate library in the future, so I think it would be better to keep it as emit