Fix traffic light snapshots outside junctions

[timothyanderson096-ocdealcheck]

Description

Standalone OpenDRIVE traffic lights use a fallback controller-registration path when their controller is not associated with a junction. That path appended the controller directly to the group's controller array, bypassing ATrafficLightGroup::AddController() and its Controller->SetGroup(this) call.

Without the owning group, WorldObserver emits a zero-initialized client snapshot: the state appears permanently Red, the OpenDRIVE signal ID is empty, and all phase timings are zero even though the server-side component accepts state changes.

This change:

• registers fallback controllers through ATrafficLightGroup::AddController()
• adds a smoke regression using a minimal OpenDRIVE map with one traffic light outside any junction
• verifies the signal ID, phase timings, and Green/Yellow/Red states after fresh world snapshots

Fixes #9832

Where has this been tested?

• Platform(s): Linux x86_64 (source-level validation)
• Python version(s): 3.12.13
• Unreal Engine version(s): Not run locally; a CARLA UE5 server/build was unavailable
• Local checks: Python syntax parsing, embedded OpenDRIVE XML parsing, line-length check, and git diff --check

The regression uses the issue reporter's runtime-proven minimal fixture and is intended to be exercised against the UE5 server by the upstream smoke-test environment.

Possible Drawbacks

The smoke suite now generates one additional minimal OpenDRIVE world, adding some runtime. The production behavior change is limited to fallback traffic-light controllers and gives them the same group registration used by the normal controller path.

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This change is 

[update-docs]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would update our CHANGELOG.md based on your changes.

[Blyron]

Hey, we are truly sorry about the delay;

Please, target ue58-dev