### 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
was_json = False
        payload = details["Payload"]
        if payload and isinstance(payload, POSSIBLE_JSON_TYPES) and payload[0] in JSON_START_CHARS:
            try:
                details["Payload"] = json.loads(details["Payload"])
                was_json = True
            except Exception:
                pass
        
        if details.get("FunctionError"):
            details["Headers"]["X-Amz-Function-Error"] = str(details["FunctionError"])
        
        logs = log_output[-4000:] if log_type == "Tail" else ""
        details["Headers"]["X-Amz-Log-Result"] = base64.b64encode(to_bytes(logs))
        details["Headers"]["X-Amz-Executed-Version"] = str(qualifier or VERSION_LATEST)
        
        response_obj = details["Payload"]
        if was_json or isinstance(response_obj, JSON_START_TYPES):
            response_obj = json_safe(response_obj)
            
            response_obj = jsonify(response_obj)
        else:
            response_obj = str(response_obj)
            details["Headers"]["Content-Type"] = "text/plain"
        return response_obj, details["StatusCode"], details["Headers"]
    
    not_found = None
    region = LambdaRegion.get()
    if arn not in region.lambdas:
        not_found = not_found_error(arn)