[BUG] PlanetaryComputer doesn't use LRO operation templates

### API Spec link

https://github.com/Azure/azure-rest-api-specs/blob/main/specification/orbital/data-plane/Microsoft.PlanetaryComputer/preview/2025-04-30-preview/openapi.json

### API Spec version

2025-04-30-preview

### Describe the bug

The fact that StacCollection is not using standard LRO operation templates is causing issues for JS SDK generation as provided in https://azure.github.io/typespec-azure/docs/getstarted/azure-core/step05/

See the discussion here https://github.com/Azure/azure-sdk-for-js/pull/36401#discussion_r2797854518

This would be a breaking change on the server side, and therefore should be addressed in a future API version

### Expected behavior

Use definition as in https://azure.github.io/typespec-azure/docs/getstarted/azure-core/step05/

### Actual behavior

In Javascript, the return result is void for long running operation becase no @lroResult is defined. It's not possible to fix this without breaking one or many operations on StacCollection

### Reproduction Steps

Regenerate JS SDK

### Environment

_No response_

Start with the 2025-04-30-preview Microsoft.PlanetaryComputer OpenAPI specification and compare the StacCollection long-running operation definitions with the Azure Core step05 LRO template. Regenerate the JavaScript SDK to reproduce the void result, then confirm the future API version's generated operation returns the intended result without changing the current version.

Written by the indexing model from the issue text.