fix: Excessive 404s on subscription metadata

[zachaysan]

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Changes

Full ticket context here, in short, subscriptions were added by default to organisations and the metadata endpoint was bypassing the free accounts because it relied on a method previously called has_subscription to 404 requests. Changes introduced:

• Renamed the method to has_paid_subscription which is closer to the intent, but still a little confusing since it includes paid subscriptions that have been canceled. I added a comment on the method, but a better method name would be even better.
• Removed the check and the 404 error since going forward we are to assume that every organisation has a related subscription model.
• Re-introduced a migration we ran in the past to create subscriptions for organisations that are missing them. This is for the small number of organisations that lacked subscriptions due to a temporary bug earlier in the year.

How did you test this code?

I updated the one test that was designed for the 404 page and ran tests from around where the code has changed.

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