### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

PutMetricData with arrays of values does not work properly. Zero values seem to be published. PutMetricData with a single value works as expected. This happens to both CLI and SDK.

### Expected Behavior

PutMetricData with arrays of values should work as publishing a single value.

### How are you starting LocalStack?

With a `docker run` command

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

    docker run localstack/localstack:1.2.0

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)
```
awslocal cloudwatch put-metric-data --namespace test --metric-data MetricName=TestCounter,Values=10,1,Counts=1,1
awslocal cloudwatch get-metric-statistics --namespace test --metric-name TestCounter --statistics Maximum --period 60 --start-time 2022-11-9T00:00:00Z --end-time 2022-11-11T00:00:00Z
{
    "Label": "TestCounter",
    "Datapoints": [
        {
            "Timestamp": "2022-11-09T23:25:10+00:00",
            "Maximum": 0.0,
            "ExtendedStatistics": {}
        },
        {
            "Timestamp": "2022-11-09T23:27:10+00:00",
            "Maximum": 0.0,
            "ExtendedStatistics": {}
        }
    ]
}
```



### Environment

```markdown
- OS: Mac Monterey
- LocalStack: 1.2.0
```


### Anything else?

_No response_
def __init__(self, message: str):
        super().__init__("ValidationError", message, 400, True)
def _set_alarm_actions(context, alarm_names, enabled):
    backend = cloudwatch_backends[context.account_id][context.region]
    for name in alarm_names:
        alarm = backend.alarms.get(name)
        if alarm:
            alarm.actions_enabled = enabled
def _cleanup_describe_output(alarm):
    reason_data = alarm.get("StateReasonData")
    if reason_data is not None and reason_data in ("{}", ""):
        alarm.pop("StateReasonData")
    if (
        alarm.get("StateReason", "") == MOTO_INITIAL_UNCHECKED_REASON
        and alarm.get("StateValue") != StateValue.INSUFFICIENT_DATA
    ):
        alarm["StateValue"] = StateValue.INSUFFICIENT_DATA
class CloudwatchProvider(CloudwatchApi, ServiceLifecycleHook):
    """
    Cloudwatch provider.
    LIMITATIONS:
        - no alarm rule evaluation
    """
    def __init__(self):