### Is there an existing issue for this?

- [X] I have searched the existing issues

### Feature description

Basically we want to only run the lambda when an insert is occurring in DynamoDB.
I tested using Dynobase deleting a record and the lambda still triggered.

```
resource "aws_lambda_event_source_mapping" "event-log" {
	event_source_arn  = aws_dynamodb_table.event-log.stream_arn
	function_name     = module.main.lambda-arn
	starting_position = "LATEST"
	enabled = true # change to false when truncating the table in localstack
	maximum_retry_attempts = 1 # limit retry on failure to 1 for now

	# https://dev.to/aws-builders/filtering-dynamodb-streams-before-lambda-p5p
	filter_criteria { # Doesn't seem to work on LocalStack for now
		filter {
			pattern = jsonencode({
				body = {
					eventName : ["INSERT"]
				}
			})
		}
	}
}
```


### 🧑‍💻 Implementation

_No response_

### Anything else?

 https://dev.to/aws-builders/filtering-dynamodb-streams-before-lambda-p5p
def _process_messages_for_event_source(self, source, messages):
        lambda_arn = source["FunctionArn"]
        queue_arn = source["EventSourceArn"]
        
        report_partial_failures = "ReportBatchItemFailures" in source.get(
            "FunctionResponseTypes", []
        )
        region_name = queue_arn.split(":")[3]
        queue_url = aws_stack.sqs_queue_url_for_arn(queue_arn)
        LOG.debug("Sending event from event source %s to Lambda %s", queue_arn, lambda_arn)
        res = self._send_event_to_lambda(
            queue_arn,
            queue_url,
            lambda_arn,
            messages,
            region=region_name,
            report_partial_failures=report_partial_failures,
        )
        return res
    def _send_event_to_lambda(
        self, queue_arn, queue_url, lambda_arn, messages, region, report_partial_failures=False
    ) -> bool:
        records = []
        def delete_messages(result: InvocationResult, func_arn, event, error=None, **kwargs):
            if error:
                
                
                
                
                return