Lambda processor should support additional batching option

Is your feature request related to a problem? Please describe.
Current aws lambda thresholds determine when to send the request and if the processor receives a large batch of events from the source, entire batch is split into requests based on the threshold parameters and sent to lambda service asynchronously and then waits for the response. This often results in lambda processor running into connection issues and the pipeline running into memory issues.

Describe the solution you'd like
We need to add another threshold option to limit the number of asynchronous requests and wait for the completion of those requests.

   aws_lambda:
      max_async_requests: <number>

Describe alternatives you've considered (Optional)
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

Start by locating the AWS Lambda processor, its existing threshold configuration, and the asynchronous request handling for large batches. Clarify how max_async_requests should limit in-flight requests and when processing should wait for completion. Done means the new option is accepted and enforced, with coverage for large-batch behavior.