VideoPress: videopress/v1/stats endpoint fails when the Jetpack plugin is not active

The `videopress/v1/stats` endpoint relies on the `sites/%d/stats/video-plays` WPCOM endpoint, that is only available if the Jetpack Stats module is active.

Currently, the Jetpack Stats module is only active if the Jetpack plugin is active, and therefore the `videopress/v1/stats` will not work properly without the Jetpack plugin active.

In this scenario, the response from `sites/%d/stats/video-plays` is as follow:

```
{
"code": 404,
"headers": [
{
"name": "Content-Type",
"value": "application\/json"
}
],
"body": {
"error": "invalid_blog",
"message": "This blog does not have the Stats module enabled"
}
}
```

We need to find a way to have the stats available when only the standalone VideoPress plugin is active.

Start by tracing the videopress/v1/stats endpoint and its request to sites/%d/stats/video-plays, then inspect how the standalone VideoPress plugin enables or accesses the Jetpack Stats module. Done means videopress/v1/stats returns video statistics when only the standalone VideoPress plugin is active, rather than the invalid_blog response.

Written by the indexing model from the issue text.