### 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_
alarm_name = "a-%s" % short_uid()
        cloudwatch_client.put_metric_alarm(
            AlarmName=alarm_name,
            EvaluationPeriods=1,
            ComparisonOperator="GreaterThanThreshold",
        )
        try:
            result = cloudwatch_client.describe_alarms(AlarmNames=[alarm_name])
            alarm = result["MetricAlarms"][0]
            assert isinstance(alarm["AlarmConfigurationUpdatedTimestamp"], datetime)
            assert isinstance(alarm["StateUpdatedTimestamp"], datetime)
        finally:
            cloudwatch_client.delete_alarms(AlarmNames=[alarm_name])
    def test_put_composite_alarm_describe_alarms_converts_date_format_correctly(
        self, cloudwatch_client
    ):
        alarm_name = "a-%s" % short_uid()
        alarm_rule = 'ALARM("my_other_alarm")'
        cloudwatch_client.put_composite_alarm(
            AlarmName=alarm_name,
            AlarmRule=alarm_rule,
        )
        try:
            result = cloudwatch_client.describe_alarms(AlarmNames=[alarm_name])
            alarm = result["CompositeAlarms"][0]
            assert alarm["AlarmName"] == alarm_name
            assert alarm["AlarmRule"] == alarm_rule
        finally:
            cloudwatch_client.delete_alarms(AlarmNames=[alarm_name])
    def test_store_tags(self, cloudwatch_client):