[TCGC] Fix subscriptionId/apiVersion client parameters for nested operation groups

[Copilot]

subscriptionId and apiVersion parameters were not being added to the top-level client's ClientInitialization when these parameters only existed in nested (non-direct-child) operation groups.

Root Cause

In addDefaultClientParameters, listOperationGroups(context, client.__raw) only returns direct children. Parameters in deeply nested operation groups were missed.

Changes

• clients.ts: Pass ignoreHierarchy=true to listOperationGroups when searching for apiVersionParam and subId parameters, enabling recursive search through all nested operation groups
• client-location.test.ts: Added test case for ARM spec with @@clientLocation moving subscriptionId to method level while verifying it remains on the client

Example

@armResourceOperations
interface Employees {
  createOrUpdate is ArmResourceCreateOrReplaceAsync<Employee, BaseParameters = EmployeeBaseParameter>;
  get is ArmResourceRead<Employee>;
}
@@clientLocation(EmployeeBaseParameter.subscriptionId, Employees.createOrUpdate);

Previously, subscriptionId was missing from the client. Now it correctly appears in client.clientInitialization.parameters.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[TCGC] ClientInitialization should have the subscriptionId parameter when subscriptionId is used at both the method and client levels</issue_title>
<issue_description>TypeSpec:

import "@typespec/http";
import "@typespec/rest";
import "@typespec/versioning";
import "@azure-tools/typespec-azure-core";
import "@azure-tools/typespec-azure-resource-manager";
import "@azure-tools/typespec-client-generator-core";

using TypeSpec.Http;
using TypeSpec.Rest;
using TypeSpec.Versioning;
using Azure.Core;
using Azure.ResourceManager;
using Azure.ClientGenerator.Core;

/** Microsoft.Contoso Resource Provider management API. */
@armProviderNamespace
@service(#{
  title: "Microsoft.Contoso management service",
})
@versioned(Microsoft.Contoso.Versions)
namespace Microsoft.Contoso;

/** The available API versions. */
enum Versions {
  /** 2021-10-01-preview version */
  @armCommonTypesVersion(CommonTypes.Versions.v5)
  v2021_10_01_preview: "2021-10-01-preview",
}

/** Employee resource */
model Employee is TrackedResource<EmployeeProperties> {
  ...ResourceNameParameter<Employee>;
}

/** Employee properties */
model EmployeeProperties {
  /** Age of employee */
  age?: int32;
  /** The status of the last operation. */
  @visibility(Lifecycle.Read)
  provisioningState?: ProvisioningState;
}

model EmployeeBaseParameter
    is Azure.ResourceManager.Foundations.DefaultBaseParameters<Employee>;

/** The resource provisioning state. */
@lroStatus
union ProvisioningState {
  ResourceProvisioningState,

  /** The resource is being provisioned */
  Provisioning: "Provisioning",

  string,
}

@armResourceOperations
interface Employees {
  createOrUpdate is ArmResourceCreateOrReplaceAsync<
    Employee,
    BaseParameters = EmployeeBaseParameter
  >;
  get is ArmResourceRead<Employee>;
}
@@clientLocation(EmployeeBaseParameter.subscriptionId, Employees.createOrUpdate);

The SubscriptionId should exist at the client.</issue_description>

<agent_instructions>In this PR: #3820, I removed the ignore hierarchy option of listOperationGroups when finding api version and subscription client parameter, which cause this regression. The reason should be when adding api version and subscription client parameter, it has not been added to __clientParametersCache which cause the missing client parameter when there are multiple layer clients. You need to fix the problem and add related test. Make sure to get all TCGC tests pass and changeset is added by pnpm -w change add.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes [TCGC] ClientInitialization should have the subscriptionId parameter when subscriptionId is used at both the method and client levels #3841

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commit: 506e73c