### 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
region = LambdaRegion.get()
    data = json.loads(request.data)
    arn = data.get("CodeSigningConfigArn")
    if arn not in region.code_signing_configs:
        msg = """The code signing configuration cannot be found.
        Check that the provided configuration is not deleted: %s.""" % (
            arn
        )
        return error_response(msg, 404, error_type="CodeSigningConfigNotFoundException")
    function_arn = func_arn(function)
    if function_arn not in region.lambdas:
        msg = "Function not found: %s" % (function_arn)
        return not_found_error(msg)
    lambda_obj = region.lambdas[function_arn]
    if data.get("CodeSigningConfigArn"):
        lambda_obj.code_signing_config_arn = arn
    result = {"CodeSigningConfigArn": arn, "FunctionName": function}
    return Response(json.dumps(result), status=200)
@app.route("/2020-06-30/functions/<function>/code-signing-config", methods=["DELETE"])
def delete_function_code_signing_config(function):
    region = LambdaRegion.get()
    function_arn = func_arn(function)
    if function_arn not in region.lambdas:
        msg = "Function not found: %s" % (function_arn)
        return not_found_error(msg)
    lambda_obj = region.lambdas[function_arn]
    lambda_obj.code_signing_config_arn = None
    return Response("", status=204)
@app.route("/2020-04-22/code-signing-configs/", methods=["POST"])
def create_code_signing_config():