API endpoint to remove collection from front (editions/feast only)

[jonathonherbert]

What's changed?

Building on #1622, adds an endpoint to remove a collection from a front, at

DELETE editions-api/front/:frontId/collection/:collectionId

I think it makes sense to scope this action to the front, as we're removing a collection from the front, and reindexing the other collections as a result. It also means we can pass back the updated front to ensure the client can read its own writes.

Implementation notes

• The automated tests should pass. They should cover happy and unhappy paths. A few unhappy paths are difficult to test because of the transactional nature of the operation (they should never fail!)
• Try pinging the endpoint locally or in CODE (you'll need to borrow a cookie from a valid browser-based request – I'd recommend importing a valid API call with 'copy to cURL' and Postman). The endpoint should work as expected.

Tested locally with cURL, and verified in client.

Checklist

General

• [x] 🤖 Relevant tests added
• [x] ✅ CI checks / tests run locally
• [ ] 🔍 Checked on CODE

Client

• [x] 🚫 No obvious console errors on the client (i.e. React dev mode errors)
• [x] 🎛️ No regressions with existing user interactions (i.e. all existing buttons, inputs etc. work)
• [x] 📷 Screenshots / GIFs of relevant UI changes included