Document ambiguity in DocumentValue filter

[einorler]

In the line here:
https://github.com/ongr-io/FilterManagerBundle/blob/master/Filter/Widget/Search/DocumentValue.php#L45
The filter only checks if the document is retrieved. However, ONGR router can be working with a number of different documents and if the intent is to filter the values on just a single one of them, the filter will do it on them all. Not only that, but the filter can crash if the other documents won't have the same field from which the values are fetched.