[python] Fix nightly build

[Copilot]

Tracks Azure/typespec-azure#3997, which deprecated @operationGroup in favor of @client (with flattened operation hierarchy) and deleted the multi-service-older-versions spec.

Package update

• Bumped @azure-tools/azure-http-specs: 0.1.0-alpha.38 → 0.1.0-alpha.39-dev.2

Deleted tests (spec removed upstream)

• test_azure_resource_manager_multi_service_older_versions.py + async counterpart
• Removed azure-resource-manager-multi-service-older-versions from requirements.txt

Updated tests (reflect flat client hierarchy)

With @client replacing @operationGroup, sub-groups are no longer generated — operations are promoted directly onto the parent client:

# Before (with @operationGroup)
client.group3.two()
client.group4.four()
client.group5.six()

# After (with @client — flat)
client.two()
client.four()
client.six()

• test_client_structure_clientoperationgroup + async: removed group3/group4/group5 sub-group access
• test_client_structure + async: updated renamed_operation (removed client.group.*) and two_operation_group (removed client.group1.*/client.group2.*)
• test_client_naming + async: Property and Header namespace operations now accessed via client.property.* and client.header.* sub-groups instead of directly on the root client

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[python] add test case for Azure/typespec-azure#3997
</issue_title>
<issue_description>follow skill https://github.com/microsoft/typespec/blob/main/.github/skills/python-sdk-spector-mock-api-tests/SKILL.md to write test case for Azure/typespec-azure#3997
</issue_description>

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

• Fixes [python] add test case for https://github.com/Azure/typespec-azure/pull/3997  #10048

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npm i https://pkg.pr.new/@typespec/http-client-python@10049

commit: 073c8fe

[github-actions]

All changed packages have been documented.

• ✅ @typespec/http-client-python

Show changes

@typespec/http-client-python - internal ✏️

Update test cases for Azure/typespec-azure#3997: replace @operationGroup with @client decorator changes. Remove deleted multi-service-older-versions tests and update client structure, naming tests to reflect new flat client hierarchy.