### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

When calling 

`cloudWatchClient.EnableAlarmActions(&cloudwatch.EnableAlarmActionsInput{AlarmNames: alarmNames})`

with golang I receive a SerializationError with bytes in the error message saying: 

`<!DOCTYPE HTM |UBLIC "-//W3C//DTD HTML 3.2 Final//EN">.<title>500 Internal Server Error</title>.<h1>Internal Server Error</h1>.<p>The server encountered an internal error and was unable to complete your request. Either the server is overloaded or there is an error in the application.`

I believe this is a bug, since other cloudwatch operations like "DescribeAlarms" work flawlessly with the same client.

### Expected Behavior

I expected the call to go through without any errors

### How are you starting LocalStack?

With a `docker run` command

### Steps To Reproduce

Start localstack, create alarms and call cloudwatch "EnableAlarmActions"

### Environment

_No response_

### Anything else?

_No response_
metric_name = "test-metric"
        namespace = "namespace"
        data = (
            "Action=PutMetricData&MetricData.member.1."
            "MetricName=%s&MetricData.member.1.Value=1&"
            "Namespace=%s&Version=2010-08-01" % (metric_name, namespace)
        )
        bytes_data = bytes(data, encoding="utf-8")
        encoded_data = gzip.compress(bytes_data)
        url = config.get_edge_url()
        headers = aws_stack.mock_aws_request_headers("cloudwatch", internal=True)
        authorization = aws_stack.mock_aws_request_headers("monitoring")["Authorization"]
        headers.update(
            {
                "Content-Type": "application/x-www-form-urlencoded; charset=utf-8",
                "Content-Length": len(encoded_data),
                "Content-Encoding": "GZIP",
                "User-Agent": "aws-sdk-nodejs/2.819.0 linux/v12.18.2 callback",
                "Authorization": authorization,
            }
        )
        request = Request(url, encoded_data, headers, method="POST")
        urlopen(request)
        rs = cloudwatch_client.list_metrics(Namespace=namespace, MetricName=metric_name)
        assert 1 == len(rs["Metrics"])
        assert namespace == rs["Metrics"][0]["Namespace"]
    def test_get_metric_data(self, cloudwatch_client):