[Firestore Mixin] - Access to the snapshot

[JaySunSyn]

Description

The firebase-firestore-mixin strips away the snapshots, only returning the data.
In my case, I want to fetch subcollections and need the path of a document which I could get from the snapshot.

Expected outcome

{__id__: "7nomMy2fdYrRSag3WbVC", __snap__: {q: t, x: t, et: t, nt: false}, data: "xyz"}

So I can get the pathvia __snap__.ref.path

Actual outcome

{__id__: "7nomMy2fdYrRSag3WbVC", data: "xyz"}