Payload empty schema

[visch]

https://github.com/kgpayne/tap-gmail/blob/main/tap_gmail/schemas/messages.json#L31

Leads to an empty schema for payload.

[visch]

Implemented the fix I did here https://github.com/AutoIDM/tap-clickup/blob/main/tap_clickup/client.py#L24-L33 but the json schema at https://github.com/kgpayne/tap-gmail/blob/main/tap_gmail/schemas/messages.json#L93 references itself and causes an infinite loop

    select:
    - "!messages.payload"
    - messages.*
    - message_list.*