Firestore State Store Metadata

[cicoyle]

The Firestore state store metadata in the docs needs to be updated.

Specifically all the fields should be validated, but for sure the required vs not required needs to be updated in the docs based on this contrib metadata.

For example, in the docs we see:

- name: private_key_id
    value: <REPLACE-WITH-PRIVATE-KEY-ID> # Optional.

but in contrib we can see:

- name: private_key_id
        type: string
        required: true

There is a discrepancy. All fields need to be validated and updated accordingly.

[cicoyle]

shoutout to @sicoyle for finding this missing information!