### 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_
backend = cloudwatch_backends[context.region]
        backend.put_metric_alarm(
            name=request.get("AlarmName"),
            namespace=None,
            metric_name=None,
            metric_data_queries=None,
            comparison_operator=None,
            evaluation_periods=None,
            datapoints_to_alarm=None,
            period=None,
            threshold=None,
            statistic=None,
            extended_statistic=None,
            description=request.get("AlarmDescription"),
            dimensions=[],
            alarm_actions=request.get("AlarmActions", []),
            ok_actions=request.get("OKActions", []),
            insufficient_data_actions=request.get("InsufficientDataActions", []),
            unit=None,
            actions_enabled=request.get("ActionsEnabled"),
            treat_missing_data=None,
            evaluate_low_sample_count_percentile=None,
            threshold_metric_id=None,
            rule=request.get("AlarmRule"),
            tags=request.get("Tags", []),
        )
        LOG.warning(
            "Composite Alarms configuration is not yet supported, alarm state will not be evaluated"
        )