### 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_
self, context: RequestContext, resource_arn: AmazonResourceName, tag_keys: TagKeyList
    ) -> UntagResourceOutput:
        self.tags.untag_resource(resource_arn, tag_keys)
        return UntagResourceOutput()
    def tag_resource(
        self, context: RequestContext, resource_arn: AmazonResourceName, tags: TagList
    ) -> TagResourceOutput:
        self.tags.tag_resource(resource_arn, tags)
        return TagResourceOutput()
    @handler("GetMetricData", expand=False)
    def get_metric_data(
        self, context: RequestContext, request: GetMetricDataInput
    ) -> GetMetricDataOutput:
        result = moto.call_moto(context)
        
        
        metric_data_queries = request["MetricDataQueries"]
        for i in range(0, len(metric_data_queries)):
            metric_query = metric_data_queries[i]
            label = metric_query.get("Label") or metric_query.get("MetricStat", {}).get(
                "Metric", {}
            ).get("MetricName")
            if label:
                result["MetricDataResults"][i]["Label"] = label
        if "Messages" not in result:
            
            result["Messages"] = []
        return result
    @handler("PutMetricAlarm", expand=False)
    def put_metric_alarm(