Pylance Typing for collections #687

Type hinting does not take into account default None values for most fields, which breaks Pylance linting

For example, a simple

    db.collection(f"mycollection").stream())

yields an error from Pylance

Argument of type "None" cannot be assigned to parameter "transaction" of type "Transaction" in function "stream"
  Type "None" cannot be assigned to type "Transaction"Pylance[reportGeneralTypeIssues](https://github.com/microsoft/pyright/blob/main/docs/configuration.md#reportGeneralTypeIssues)

I saw a similar error in #570, I think most of the type hinting should be reviewed.

Environment details

• OS type and version: MacOS 12.4
• Python version: 3.11.1
• pip version: pip 23.0
• google-cloud-firestore version: 2.9.1

Steps to reproduce

In VSCode :

    db.collection(f"mycollection").stream())