[TASK] Implement SignatureBridge event watcher for EVM

[dutterbutter]

We need to watch for Events that are emitted by the Signature Bridge Contract, specifically speaking about the GovernanceOwnershipTransferred we need to watch for that event so we make sure we cancel any pending transaction that is doing the transfer ownership if it is already transferred.

event GovernanceOwnershipTransferred(address indexed previousOwner, address indexed newOwner);

[dutterbutter]

@shekohex please update task with relevant context.