### 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
self, first_record: Dict, last_record: Dict
    ) -> Tuple[str, str]:
        """
        to be implemented by subclasses
        :returns: the SequenceNumber field values from the given records
        """
        raise NotImplementedError
    def _get_first_and_last_arrival_time(
        self, first_record: Dict, last_record: Dict
    ) -> Tuple[str, str]:
        """
        to be implemented by subclasses
        :returns: the timestamps the given records were created/entered the source stream in iso8601 format
        """
        raise NotImplementedError
    def start(self):