refactor: bls_aggregation use new struct TaskMetadata

[damiramirez]

What Changed?

This PR introduces a small refactor in task initialization by encapsulating related parameters into a new struct and simplifying function interfaces.

• Create a new struct TaskMetadata. This struct encapsulates the parameters used by InitializeNewTask() and singleTaskAggregatorGoroutineFunc().
• Add a constructor method for TaskMetadata

type TaskMetadata struct {
	taskIndex types.TaskIndex
	taskCreatedBlock uint32
	quorumNumbers types.QuorumNums
	quorumThresholdPercentages types.QuorumThresholdPercentages
	timeToExpiry time.Duration
	windowDuration time.Duration
}

func NewTaskMetadata(taskIndex types.TaskIndex, taskCreatedBlock uint32, quorumNumbers types.QuorumNums, quorumThresholdPercentages types.QuorumThresholdPercentages, timeToExpiry time.Duration) TaskMetadata
func (t TaskMetadata) WithWindowDuration(windowDuration time.Duration) TaskMetadata

func (a *BlsAggregatorService) InitializeNewTask(metadata TaskMetadata) error
func (a *BlsAggregatorService) singleTaskAggregatorGoroutineFunc(metadata TaskMetadata, signedTaskRespsC <-chan types.SignedTaskResponseDigest)

• Update BlsAggregationService interface with the new signature.
• Remove InitializeNewTaskWithWindow() since WindowDuration is now included in TaskMetadata, this function is no longer needed.
• Adjusted test cases to align with the new function signatures.

Reviewer Checklist

• Code is well-documented
• Code adheres to Go naming conventions
• Code deprecates any old functionality before removing it