fix components add by using custom ui.* registry

[PennyroyalTea]

Running npx @elevenlabs/cli@latest components add orb errored:

~/code/cli pennyroyalte…cn-repo-pull ❯ npx @elevenlabs/cli@latest components add orb
Launching shadcn/ui CLI...
Source: https://ui.elevenlabs.io

Something went wrong. Please check the error below for more details.
If the problem persists, please open an issue on GitHub.

Message:
The item at https://ui.shadcn.com/r/styles/new-york-v4/orb.json was not found. It may not exist at the registry.

Suggestion:
Check if the item name is correct and the registry URL is accessible.

this was because default shadcn registry was used instead of custom one. This PR fixes it.