### 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_
"Period": 60,
                        "Stat": "Sum",
                    },
                },
                {
                    "Id": "part",
                    "MetricStat": {
                        "Metric": {"Namespace": "ug/thing", "MetricName": "ug"},
                        "Period": 60,
                        "Stat": "Sum",
                    },
                },
            ],
            StartTime=datetime.utcnow() - timedelta(hours=1),
            EndTime=datetime.utcnow(),
        )
        assert 2 == len(response["MetricDataResults"])
        for data_metric in response["MetricDataResults"]:
            if data_metric["Id"] == "some":
                assert 41.0 == data_metric["Values"][0]
            if data_metric["Id"] == "part":
                assert 23.0 == data_metric["Values"][0]
        
        response = cloudwatch_client.get_metric_data(
            MetricDataQueries=[
                {
                    "Id": "some",
                    "MetricStat": {
                        "Metric": {
                            "Namespace": "some/thing",