### 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_
self.alarm_scheduler.shutdown_scheduler()
    def delete_alarms(self, context: RequestContext, alarm_names: AlarmNames) -> None:
        moto.call_moto(context)
        for alarm_name in alarm_names:
            arn = aws_stack.cloudwatch_alarm_arn(alarm_name)
            self.alarm_scheduler.delete_scheduler_for_alarm(arn)
    def get_raw_metrics(self, request: Request):
        region = aws_stack.extract_region_from_auth_header(request.headers)
        backend = cloudwatch_backends[region]
        if backend:
            result = backend.metric_data
        else:
            result = []
        result = [
            {
                "ns": r.namespace,
                "n": r.name,
                "v": r.value,
                "t": r.timestamp,
                "d": [{"n": d.name, "v": d.value} for d in r.dimensions],
            }
            for r in result
        ]
        return {"metrics": result}
    def list_tags_for_resource(