fix: Set realm on signup flow

[dalkia]

What does this PR change?

Sets the realm on signup flow to avoid a double loading screen on scenes deployed with sdk legacy builder

How to test the changes?

1. Enter as a new guest into enji.dcl.eth and check that you dont get a double loading screen

Our Code Review Standards

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

Copilot summary

copilot:summary

[github-actions]

After the CI passes:

Web

This branch can be previewed at:

• https://play.decentraland.org/?explorer-branch=fix/setting-realm-on-signup-flow
• https://play.decentraland.zone/?explorer-branch=fix/setting-realm-on-signup-flow

Desktop:

If you have the launcher installed (download launcher) you can press open on the following link:

• Open custom protocol
• Open custom protocol with Developer Mode

SDK 6/7:

• Open SDK7 scenes playground
• Open SDK7 scenes in preview
• Open SDK6 scenes in preview

More

• Code coverage report: https://renderer-artifacts.decentraland.org/branch-coverage/fix/setting-realm-on-signup-flow
• Benchmark report: https://renderer-artifacts.decentraland.org/branch-benchmark/fix/setting-realm-on-signup-flow/index.html

[Ludmilafantaniella]

✅ Fix verified and approved.

1. I launch DCL as a guest using the URL with the realm set as enji.dcl.eth.
2. It accesses the world correctly without triggering the tutorial.
3. Tested on Browser & Desktop

[dalkia]

Closed as being released as hotfix at #6047