### 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
policy = [d for d in docs if d["PolicyName"] == policy_name]
    if policy:
        return policy[0]
    
    res_qualifier = func_qualifier(function, qualifier)
    policy = [d for d in docs if d["Statement"][0]["Resource"] == res_qualifier]
    return (policy or [None])[0]
def get_lambda_policy_name(resource_name: str, qualifier: str = None) -> str:
    qualifier = qualifier or "latest"
    if ":function:" in resource_name:
        resource_name = function_name_from_arn(resource_name)
    return LAMBDA_POLICY_NAME_PATTERN.format(name=resource_name, qualifier=qualifier)
def lookup_function(function, region, request_url):
    result = {
        "Configuration": function,
        "Code": {"Location": "%s/code" % request_url},
        "Tags": function["Tags"],
    }
    lambda_details = region.lambdas.get(function["FunctionArn"])
    
    
    if lambda_details.package_type == "Image":
        result["Code"] = lambda_details.code
        result["Configuration"]["CodeSize"] = 0
        result["Configuration"].pop("Handler", None)
        result["Configuration"].pop("Layers", None)
    if lambda_details.concurrency is not None:
        result["Concurrency"] = lambda_details.concurrency
    return jsonify(result)
def not_found_error(ref=None, msg=None):