Allows new role field in the onboarding_status jsonb column

What does this MR do and why?

This is the first step to prepare the move of the role column in user table to the onboarding_status jsonb column in the user_detail table here: #498739.

This MR allow new role field in the onboarding_status jsonb column

• we must add them first here due to our setting of "additionalProperties": false before using and deploy it out to the entire GitLab.com environment. If we do not deploy this before using we could get into a case where we store a value on canary and then try to save a user update on non-canary and cause an error on user validation.

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