[FR]: Add async await to addDocument to collection with the parameter Codable

[jesus-mg-ios]

Description

There's an implementation but with a [String:Any] map

API Proposal

Do the same with a Codable parameter

Firebase Product(s)

Firestore

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[peterfriese]

This is related to #9157