### 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_
client = get_cloudwatch_client_for_region_of_alarm(alarm_arn)
    metric_values = collect_metric_data(alarm_details, client)
    alarm_name = alarm_details["AlarmName"]
    alarm_state = alarm_details["StateValue"]
    treat_missing_data = alarm_details.get("TreatMissingData", "missing")
    empty_datapoints = metric_values.count(None)
    if empty_datapoints == len(metric_values):
        if treat_missing_data == "missing":
            update_alarm_state(
                client,
                alarm_name,
                alarm_state,
                STATE_INSUFFICIENT_DATA,
                f"{INSUFFICIENT_DATA}: empty datapoints",
            )
        elif treat_missing_data == "breaching":
            update_alarm_state(
                client,
                alarm_name,
                alarm_state,
                STATE_ALARM,
                f"{THRESHOLD_CROSSED}: empty datapoints - treated as breaching",
            )
        elif treat_missing_data == "notBreaching":
            update_alarm_state(
                client,
                alarm_name,
                alarm_state,
                STATE_OK,
                f"{THRESHOLD_OK}: empty datapoints - treated as notBreaching",