Chore: refactor out the legacy pro plan API code

[jpmcb]

Type of feature

📦 Chore

Current behavior

Related to:

• https://github.com/open-sauced/app/issues/2877

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We're going all in on the Pro Workspace pricing. So this means we can get rid of the legacy pro plan stuff in the API. There isn't much but it mostly revolves around "role".

Suggested solution

Remove legacy "user_role" Pro plan pricing code. This will probably be a long standing issue since we'll roll this out slowly.

Additional context

No response

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