feat(ai): enable AI orchestrator discovery

This commit incorporates the AIServiceRegistry contract address, superseding the conventional ServiceRegistry contract address. This strategic alteration streamlines the discovery process of AI Orchestrators within the AI Subnet, thereby bolstering network accessibility and interaction. While this approach serves as a swift workaround to enable the feature without extensive code modification, it's important to note that it may disrupt the existing transcoding discovery mechanism. We have to fix this if we want to merge the two networks in the future.

[!WARNING] Do not merge into the main branch this pull request breaks the discovery of the regular transcoding network.

What does this pull request do? Explain your changes. (required)

This pull request implements https://linear.app/livepeer-ai-spe/issue/LIV-90/design-and-implement-solution-for-advertising-separate-service-uri-for so that AI subnet orchestrators can be found by the AI gateway.

Specific updates (required)

serviceRegistryAddr was changed to a newly deployed AIServiceRegistroyProxy contract.

How did you test each of these updates (required)

I checked if the service URIs of the orchestrators were to the values stored in the AIServiceRegistroyProxy contract. I have yet to test if an on-chain broadcaster can still send jobs.

Does this pull request close any open issues?

https://linear.app/livepeer-ai-spe/issue/LIV-90/design-and-implement-solution-for-advertising-separate-service-uri-for

Checklist:

[x] Read the contribution guide
[x] make runs successfully
[x] All tests in ./test.sh pass
[x] README and other documentation updated
[x] Pending changelog updated

livepeer / go-livepeer

feat(ai): enable AI orchestrator discovery #3004