feat: asset bundle fallback

[dalkia]

What does this PR change?

• Makes the scene definition to be fetched from the AB registry instead of the Catalyst Active Endpoints
• Behind feature flag

How to test the changes?

1. The first test phase should be done in zone.
2. Create a scene using the builder and deploy it
3. Open the client using --dclenv zone
4. Go to you scene, you should see it
5. Using the builder, create a broken state. IE: delete all images so the ABConverter fails. Deploy it
6. Go back to the client. You should still be able to see it

Our Code Review Standards

https://github.com/decentraland/unity-renderer/blob/master/docs/code-review-standards.md

[github-actions]

Windows and Mac build successfull in Unity Cloud! You can find a link to the downloadable artifact below.

Name	Link
Commit	cc9ac08
Logs	https://github.com/decentraland/unity-explorer/actions/runs/12396208932
Download Windows	https://github.com/decentraland/unity-explorer/suites/32221128451/artifacts/2338545869
Download Windows S3	https://explorer-artifacts.decentraland.org/@dcl/unity-explorer/branch/feat/asset-bundle-fallback/Decentraland_windows64.zip
Download Mac	https://github.com/decentraland/unity-explorer/suites/32221128451/artifacts/2338558814
Download Mac S3	https://explorer-artifacts.decentraland.org/@dcl/unity-explorer/branch/feat/asset-bundle-fallback/Decentraland_macos.zip
Built on	2024-12-18T16:06:14Z

[Ludmilafantaniella]

Here’s what we validated during the process:

1. Fall-back to the most recent outdated scene bundle: ✅ Passed successfully.
2. Correct bundle retrieval for updated scenes: ✅ Also passed without issues.
3. Validate local cache removal for non-active scenes: ❌ This point failed because the reload functionality hasn’t been implemented yet, and Juani confirmed it won’t be ready in time.

Additional Notes:

• The bug we encountered was related to the back-end and didn’t affect our testing results. 182 (dapps)
• We couldn’t test the unpublish flow, meaning the modification of scene pointers (shrink or expand) still needs to be validated.

Untitled.video.-.Made.with.Clipchamp.mp4